Focus on Evolution and MigrationVisit the Evolution SiteIllegal immigration refers to immigration across national borders in a way that violates the immigration laws of the destination country. In politics, the term may imply a larger set of social issues and time constraints with disputed consequences in areas such as economy, social welfare, education, health care, slavery, prostitution, crime, legal protections, voting rights, public services, and human rights. Illegal emigration, in contrast, refers to unlawfully leaving a country.
Creationists who want religious ideas taught as scientific fact in public schools continue to adapt to courtroom defeats by hiding their true aims under ever changing guises
Craigslist to change erotic services section to require working phone number and credit card charge. Information to be given to police upon subpoena.
"Requiring credit-card verification, and charging a fee to post in this category raises accountability to a point where we expect few illicit ads will remain," CEO Jim Buckmaster said. He said that "more than ever, those who would misuse Craigslist to violate the law will find that Craigslist is a very inhospitable place."
The San Francisco -based service also said it had filed 14 lawsuits against businesses selling software and other services designed to evade its terms of use.
The days of, "That's the way we've always done it," are gone. Understanding the
ethical decision-making process has become a critical tool for those who lead America's
In relation to the Virtues of Selfishness (Rand, 1964), one comes to understand the
importance of shielding himself from those who would rob him of the time and talent that
To understand how Rand’s philosophy is reflected in this novella, one must first
know the story. The following is a brief synopsis:
Who is Ayn Rand8:17 AM [Factored from [[Who is Ayn Rand]]] Anon - 1 changes - 43 hits
Who is Ayn Rand?
Understanding Rand’s history is essential to understanding and appreciating her
storylines. Ayn Rand (Alissa Rosnbaum) was born in Russia, in 1905. She taught herself
There is a wealth of evidence linking family breakdown with many adverse health outcomes for children and society as a whole. Government policy therefore should be to strengthen the marriage-based family of husband and wife. ‘Gay marriages’, with their inherent instability, will contribute to the many adverse effects family breakdown has on children and on society as a whole.
At the root of many of the problems we see in children and young adults - such as emotional and behavioral difficulties, poor school performance, substance misuse, precocious teenage sexuality including teenage pregnancy and juvenile delinquency - is the dramatic increase in family breakup and ‘relationship turnover’ of parents, adversely affecting their children(For anoverview see: Rebecca O’Neill. Experiments in living. CIVITAS. 2002)
‘Gay marriage’ and homosexuality some medical comments
Authors of this report: John Shea,MD, FRCP (C), Radiologist; John K. Wilson MD, FRCP (C), Cardiologist; Paul Ranalli MD, FRCP (C), Neurologist; Christina Paulaitis MD, CCFP, Family Physician; Luigi Castagna MD, FRCP (C), Paediatric Neurologist; Hans-Christian Raabe MD, MRCP MRCGP Internist; W. André Lafrance MD, FRCP (C),Dermatologist
There are significant benefits from (heterosexual) marriage for individual and society.Heterosexually married couples are, on average, healthier, have fewer psychological problems andlive longer than cohabiting or single individuals. Government policy therefore should be to support and strengthen heterosexual marriage.
In reviews by Professor Oswald, Professor of Economics at Warwick University, UK it was found that marriage reduces mortality. The excess mortality of men who are not married is similar to the excess mortality by smoking. Marriage has a much more important effect on longevity than income does. For men, the effect is positive and substantial. It almost exactlyoffsets the large (negative) consequences of smoking. For women, the effect is approximately half the size of the smokingeffect.
Despite all the impression given by the media, homosexuality is neither an entirely innate condition nor is it unchangeable. The so-called ‘gay gene’ has never been found. There are studies that show it is possible to change sexual orientation from predominantly homosexual to predominantlyheterosexual orientation.
A recent review by authors sympathetic to the gay movement shows clearly that homosexual development cannot be only determined by genes. Evidence from biology shows clearly that gays are not simply born that way. Environmental influences play a significant role in the development of gender identity and sexual behavior. (Bailey JM. Biological perspectiveson sexual orientation. In: Garnets LD and Kimmel DC: Psychological perspectives on lesbian, gay, and bisexual experiences. Columbia University Press, New York. 2003)*There is no convincing evidence for a ‘gay gene’. Indeed, if there were a ‘gay gene’ those who carry it would probably be at adisadvantage in the natural selection process of evolution: ‘If there was a ‘gay gene’ this gene would cause a significant problem: homosexuality is associated with low fertility, indeed if a homosexual has only sex with same-sex persons he will have no offspring.’ (Bailey JM. Biological perspectives on sexual orientation. 2003)*One way of finding out whether a condition is genetically determined is to examine the behavior of identical twins (who have the same genetic material) and comparing them with non-identical twins. It is assumed, that twins grow up in the sameenvironment, There have been several studies investigating whether the identical twin brothers of homosexual men are alsohomosexuals. Concordance (both identical twins being homosexual) was found in only 25-50% of identical twin pairs. ‘Genes’ therefore cannot entirely explain homosexual orientation and behaviour. (Pillard RC and Weinrich JD. Evidence of
Any attempts to legalise gay marriage should be aware of the link between homosexuality and pedophilia. While the majority of homosexuals are not involved in pedophilia, it is of grave concern that there is a disproportionately greater number of homosexuals among pedophiles and an overlapbetween the gay movement and the movement to make pedophilia acceptable
One well known historic example on the link between homosexuality and pedophilia is found in ancient Greece. Greekmythology is saturated with stories of pedophilia and ancient Greek literature praises pedophilia. The age group of boys thatwere used for ‘sexual pleasure’ was probably in the range of 12-17. Male prostitution was very common with brothels in which boys and young men were available. There is evidence for an extensive trade in boys. (Churchill W. Homosexual Behavioramong Males. Hawthorn. New York. 1967)
Gay activists claim that there is no difference between children raised in a homosexual as opposed to a heterosexual household. However, essentially all studies that show that there is no difference have been criticised because of poor research quality. Despite the shortcomings, the studies seemto suggest that children raised in same-sex parents may be more sexually promiscuous and morelikely to become homosexuals.
In a review of all the studies that purport to find no difference between children raised in families by same-sex parents andparents of different sex, major methodological flaws have been noted. For example, the studies have very small sample sizes, biased sample selection, or lack of control groups. (P. Morgan, Children as Trophies? Christian Institute. Newcastle upon Tyne, 2002)
The media portrays the homosexual lifestyle and relationships as happy, healthy and stable. However, the homosexual lifestyle is associated with a large number of very serious physical and emotional health consequences. Many ‘committed’ homosexual relationships only last a few years.
This raises doubts as to whether children raised in same-sex households are being raised in aprotective environment.
Apple, Google Both Come Out Corporately Against Traditional Marriage Definition Ballot Measure
Apple donates $100,000 to campaign against Proposition 8 In California
CALIFORNIA, October 24, 2008 (http://www.LifeSiteNews.com) - Two of the world's largest computer tech companies, Apple and Google, have taken the unusual corporate action of opposing a California ballot measure, Proposition 8, which would insert the traditional definition of marriage in the state consistution.
The total complement of genes in an organism or cell is known as its [genome]Create?, which may be stored on one or more [chromosome]Create?s; the region of the chromosome at which a particular gene is located is called its [locus]Create?. A chromosome consists of a single, very long DNA helix on which thousands of genes are encoded. Prokaryotes - [bacteria]Create? and archaea - typically store their genomes on a single large, circular chromosome, sometimes supplemented by additional small circles of DNA called plasmids, which usually encode only a few genes and are easily transferable between individuals. For example, the genes for antibiotic resistance are usually encoded on bacterial plasmids and can be passed between individual cells, even those of different species, via horizontal gene transfer.
Although some simple eukaryotes also possess plasmids with small numbers of genes, the majority of eukaryotic genes are stored on multiple linear chromosomes, which are packed within the nucleus in complex with storage proteins called histones. The manner in which DNA is stored on the histone, as well as chemical modifications of the histone itself, are regulatory mechanisms governing whether a particular region of DNA is accessible for gene expression. The ends of eukaryotic chromosomes are capped by long stretches of repetitive sequences called telomeres, which do not code for any [gene product]Create? but are present to prevent degradation of coding and regulatory regions during [DNA replication]Create?. The length of the telomeres tends to decrease each time the genome is replicated in preparation for cell division; the loss of telomeres has been proposed as an explanation for cellular senescence, or the loss of the ability to divide, and by extension for the aging process in organisms. (
In some cases, RNA is an intermediate product in the process of manufacturing proteins from genes. However, for other Gene sequences, the RNA molecules are the actual functional products. For example, RNAs known as ribozymes are capable of enzymatic function, and miRNAs have a regulatory role. The [DNA]Create? sequences from which such RNAs are transcribed are known as RNA genes.
Some [virus]Create?es store their entire genomes in the form of RNA, and contain no DNA at all. Because they use RNA to store genes, their [cellular]Create? hosts may synthesize their proteins as soon as they are infected and without the delay in waiting for transcription. On the other hand, RNA [retrovirus]Create?es, such as HIV, require the reverse transcription of their [genome]Create? from RNA into DNA before their proteins can be synthesized.
Changing concept of Gene7:27 PM [Factored from [[Changing concept of gene]]] Anon - 2 changes - 83 hits
The concept of the Gene has changed considerably (see history section). From the original definition of a "unit of inheritance", the term evolved to mean a [DNA]Create?-based unit that can exert its effects on the organism through RNA or protein products. It was also previously believed that one Gene makes one protein; this concept was overthrown by the discovery of alternative splicing and trans-splicing.
The definition of a Gene is still changing. The first cases of RNA-based inheritance have been discovered in mammals. (Rassoulzadegan and colleagues (2006) RNA-mediated non-Mendelian inheritance of an epigenetic change in the mouse. PMID 16724059) Evidence is also accumulating that the control regions of a Gene do not necessarily have to be close to the coding sequence on the linear [molecule]Create? or even on the same [chromosome]Create?. Spilianakis and colleagues discovered that the promoter region of the interferon-gamma gene on [chromosome]Create? 10 and the regulatory regions of the T(H)2 cytokine locus on [chromosome]Create? 11 come into close proximity in the nucleus possibly to be jointly regulated. (Spilianakis & colleagues (2005) Interchromosomal associations between alternatively expressed loci. PMID 15880101)
The growth, development, and reproduction of organisms relies on cell division, or the process by which a single [cell]Create? divides into two usually identical daughter cells. This requires first making a duplicate copy of every gene in the [genome]Create? in a process called [DNA replication]Create?. The copies are made by specialized enzymes known as DNA polymerases, which "read" one strand of the double-helical DNA, known as the template strand, and synthesize a new complementary strand. Because the DNA double helix is held together by [base pair]Create?ing, the sequence of one strand completely specifies the sequence of its complement; hence only one strand needs to be read by the enzyme to produce a faithful copy. The process of DNA replication is semiconservative; that is, the copy of the genome inherited by each daughter cell contains one original and one newly synthesized strand of DNA. (
(#11) )
[right|thumbnail|270px|This stylistic diagram shows a gene in relation to the double helix structure of [[DNA]Create? and to a [chromosome]Create? (right). Introns are regions often found in eukaryote genes that are removed in the splicing process (after the DNA is transcribed into RNA): only the exons encode the protein. This diagram labels a region of only 40 or so bases as a gene. In reality most genes are hundreds of times larger.]]
Amber eyes are of a solid color and have a strong yellowish/golden and russet/coppery tint. This might be due to the deposition of the yellow pigment called "lipochrome" in the iris (which is also found in green and violet eyes). (Howard Hughes Medical Institute: Ask A Scientist) (Eye Color) They are nicknamed "Wolf eyes" due to the high rate of the amber eye color in wolves. Amber eyes should not be confused with hazel eyes; although hazel eyes may contain specks of amber or gold, they usually tend to comprise of many other colors, including green, brown and orange. Also, hazel eyes may appear to shift in color and consist of flecks and ripples; while amber eyes are of a solid gold hue.
The eyes of some pigeons contain yellow fluorescing pigments known as pteridines. (Oliphant LW. "Observations on the pigmentation of the pidgeon iris." Pigment Cell Res. 1987; 1(3):202-8. PMID 3508278.) The bright yellow eyes of the Great Horned Owl are thought to be due to the presence of the pteridine pigment xanthopterin within certain chromatophores (called xanthophores) located in the iris stroma. (Oliphant LW. "Crystalline pteridines in the stromal pigment cells of the iris of the great horned owl." Cell Tissue Res. 1981; 217(2):387-95. PMID 7237534.) In humans, yellowish specks or patches are thought to be due to the pigment lipofuscin, also known as lipochrome.
Gray eyes have less melanin than blue eyes, even though they are considered a darker shade of blue (like blue-green). They are most common in European Russia, Finland and the Baltic States. Under magnification, gray eyes exhibit small amounts of yellow and brown color in the iris.
A gray iris may indicate the presence of a uveitis. However, other visual signs make a uveitis obvious.
Aniridia is a congenital condition characterized by an extremely underdeveloped iris which appears absent on superficial examination. (eMedicine - Aniridia : Article by Daljit Singh)
See also:
Hazel eyes are due to a combination of a Rayleigh scattering and a moderate amount of melanin in the iris' anterior border layer. (Lefohn, A., Budge, B., Shirley, P., Caruso, R., and Reinhard, E. 2003. An Ocularist's Approach to Human Iris Synthesis. IEEE Comput. Graph. Appl. 23, 6 (Nov. 2003), 70-75. DOI= http://dx.doi.org/10.1109/MCG.2003.1242384) Hazel eyes often appear to shift in color from a light brown to a medium golden-green. A number of studies using three-point scales have assigned "hazel" to be the medium-color between the lightest shade of blue and darkest shade of brown. (Zhu G, Evans DM, Duffy DL, Montgomery GW, Medland SE, Gillespie NA, Ewen KR, Jewell M, Liew YW, Hayward NK, Sturm RA, Trent JM, Martin NG. "A [genome]Create? scan for eye color in 502 twin families: most variation is due to a QTL on [chromosome]Create? 15q." 1: Twin Res. 2004 Apr; 7(2):197-210. PMID 15169604.) (Albert DM, Green WR, Zimbric ML, Lo C, Gangnon RE, Hope KL, Gleiser J. "Iris melanocyte numbers in Asian, African American, and Caucasian irides."Trans Am Ophthalmol Soc. 2003; 101:217-21; discussion 221-2. PMID 14971580.) (Mitchell R, Rochtchina E, Lee A, Wang JJ, Mitchell P; Blue Mountains Eye Study. "Iris color and intraocular pressure: the Blue Mountains Eye Study." Am J Ophthalmol. 2003 Mar; 135(3):384-6. PMID 12614760.) (Lindsey JD, Jones HL, Hewitt EG, Angert M, Weinreb RN. "Induction of tyrosinase Gene transcription in human iris organ cultures exposed to latanoprost." Arch Ophthalmol. 2001 Jun; 119(6):853-60. PMID 11405836.) (Frank RN, Puklin JE, Stock C, Canter LA. "Race, iris color, and age-related macular degeneration."Trans Am Ophthalmol Soc. 2000; 98:109-15; discussion 115-7. PMID 11190014.) (Regan S, Judge HE, Gragoudas ES, Egan KM. "Iris color as a prognostic factor in ocular melanoma." Arch Ophthalmol. 1999 Jun; 117(6):811-4. PMID 10369595.) (Hawkins TA, Stewart WC, [McMillan]Create? TA, Gwynn DR. "Analysis of diode, argon, and Nd: YAG peripheral iridectomy in cadaver eyes." Doc Ophthalmol. 1994; 87(4):367-76. PMID 7851220.) This can sometimes produce a multicolored iris, i.e., an eye that is light brown near the pupil and charcoal or amber/dark green on the outer part of the iris (and vice versa) when observed in sunlight. Hazel is commonly found in some regions of the Middle East, Europe, North America, parts of Central Asia, parts of North India, Northern Pakistan and in Afghanistan. Rarely, hazel eyes can be found in people of sub-saharan African, Native American and East Asian descent.
Definitions of the eye color "hazel" vary: it is sometimes considered to be synonymous with light-brown and gold. (Understanding Genetics: Human Health and the Genome) (Naldi L, Altieri A, Imberti GL, Giordano L, Gallus S, La Vecchia C; Oncology Study Group of the Italian Group for Epidemiologic Research in Dermatology (GISED). "Cutaneous malignant melanoma in women. Phenotypic characteristics, sun exposure, and hormonal factors: a case-control study from Italy." Ann Epidemiol. 2005 Aug; 15(7):545-50. PMID 16029848.) (April Holladay. "Funny — you can't hide those lightening eyes." USATODAY.com. October 8, 2004. Retrieved September 17, 2006.) (English JS, Swerdlow AJ, [MacKie]Create? RM, O'Doherty CJ, Hunter JA, Clark J, Hole DJ. "Relation between ³640³ and banal melanocytic naevi."Br Med J (Clin Res Ed). 1987 Jan 17; 294(6565):152-4. PMID 3109545.) (Hara T. "[Increased iris pigmentation after use of latanoprost in Japanese brown eyes.]" Nippon Ganka Gakkai Zasshi. 2001 May; 105(5):314-21. PMID 11406947.) In North America, "hazel" is often used to describe eyes that appear to change color, ranging from light brown to green and even gray, depending on lighting in the environment.
Eye colors can range from the most common color, brown, to the least common, green. Rare genetic mutations can even lead to unusual eye colors: black, red, and violet. eye color is an inherited trait influenced by more than one gene. (Sturm RA, Frudakis TN. color: portals into pigmentation genes and ancestry."Trends Genet. 2004 Aug; 20(8):327-32. PMID: 15262401.) (Grant MD, Lauderdale DS. "Cohort effects in a genetically determined trait: eye color among US whites." Ann Hum Biol. 2002 Nov-Dec; 29(6):657-66. PMID 12573082.) These genes are being sought using associations to small changes in the genes themselves and in neighboring genes. These changes are known as single nucleotide polymorphisms or SNPs. The actual number of genes that contribute to eye color is unknown at present, but there are a few likely candidates.
The gene OCA2 (), when in a variant form the gene causes the pink eye color and hypopigmentation common in human [albinism]Create?, (the name of the gene is derived from the disorder it causes, oculocutaneous albinism type II). Different SNPs within OCA2 are strongly associated with brown and green eyes as well as variations in freckling, mole counts, hair and skin tone. The polymorphisms may be in an OCA2 regulatory sequence, where they may influence the expression of the [gene product]Create?, which in turn affects pigmentation. (Duffy DL, Montgomery GW, Chen W, Zhao ZZ, Le L, James MR, Hayward NK, Martin NG, and Sturm, RA "A Three–Single-Nucleotide Polymorphism ³670³ in Intron 1 of OCA2 Explains Most Human Eye-color Variation"Am. J. Hum. Genet. 2002 80:000, 2007.) A specific Mutation within the HERC2 gene, a gene that regulates OCA2 expression, is partly responsible for blue eyes. ( Kayser M, Liu F, Janssens AC, Rivadeneira F, Lao O, van Duijn K, Vermeulen M, Arp P, Jhamai MM, van Ijcken WF, den Dunnen JT, Heath S, Zelenika D, Despriet DD, Klaver CC, Vingerling JR, de Jong PT, Hofman A, Aulchenko YS, Uitterlinden AG, Oostra BA, van Duijn CM. "Am J Hum Genet." 2008 Feb; 82(2):411-23.) Other genes implicated in eye color variation are: [SLC24A4]Create? (Sulem P, Gudbjartsson DF, Stacey SN, Helgason A, Rafnar T, Magnusson KP, Manolescu A, Karason A, Palsson A, Thorleifsson G, Jakobsdottir M, Steinberg S, Pálsson S, Jonasson F, Sigurgeirsson B, Thorisdottir K, Ragnarsson R, Benediktsdottir KR, Aben KK, Kiemeney LA, Olafsson JH, Gulcher J, Kong A, Thorsteinsdottir U, Stefansson K. "Nature Genetics" 2007 Dec; 39(12):1443-52.PMID: 17952075) , TYR .
Iris color can provide a large amount of information about an individual and a classification of various colors may be useful in documenting pathological changes or determining how a person may respond to various ocular pharmaceuticals. (German EJ, Hurst MA, Wood D, Gilchrist J. "A novel system for the objective classification of iris color and its correlation with response to 1% tropicamide." Ophthalmic Physiol Opt. 1998 Mar; 18(2):103-10. PMID 9692029.) Various classification systems have ranged from a basic "light" or "dark" description to detailed gradings employing photographic standards for comparison. Others have attempted to set objective standards of color comparison. (Fan S, Dyer CR, Hubbard L. Quantification and Correction of Iris Color." Technical report 1495, University of Wisconsin-Madison, Dec, 2003.)
As the perception of color is dependent on viewing conditions (e. g. the amount and type of illumination, as well as the hue of the surrounding environment), so is the perception of eye color. (Color Perception)
The eyes of a person with [albinism]Create? may appear red under certain lighting conditions due to the very low quantities of melanin. "True" red eyes also exist in albinistic populations, but are very rare.
Those with lighter iris color have been found to have a higher prevalence of age-related macular degeneration (ARMD) than those with darker iris color; lighter eye color is also associated with an increased risk of ARMD progression. (Nicolas CM, Robman LD, Tikellis G, Dimitrov PN, Dowrick A, Guymer RH, [McCarty]Create? CA. "Iris colour, ethnic origin and progression of age-related macular degeneration." Clin Experiment Ophthalmol. 2003 Dec; 31(6):465-9. PMID 14641151.) An increased risk of uveal melanoma has been found in those with blue, green or gray iris color. (Stang A, Ahrens W, Anastassiou G, Jockel KH. "Phenotypical characteristics, lifestyle, social class and uveal melanoma." Ophthalmic Epidemiol. 2003 Dec;10(5):293-302. PMID 14566630.)
Eye color may also be symptomatic of disease. Aside from the iris, yellowing of the whites of the eyes is associated with jaundice and symptomatic of liver disease, including cirrhosis, hepatitis and malaria.
External links of eye color7:27 PM [Factored from [[External links of eye color]]] Anon - 1 changes - 34 hits
Often, white newborns have blue eyes, which change to green, hazel, light brown or dark brown. This is possibly the origin of the idiom "being blue-eyed" (i. e. naïve; gullible).
It is thought that exposure to light after birth triggers the production of melanin in the iris of the eye. By three years of age, the eyes produce and store enough melanin to indicate their natural shade. While changes in eye color of infants are more common, even in adults, eye color changes are seen, most often as a result of exposure to the sun. Sunlight triggers melanin production in the eye, as it does to the skin.
See also of eye color7:27 PM [Factored from [[See also of eye color]]] Anon - 1 changes - 46 hits
Heterochromia (also known as a heterochromia iridis or heterochromia iridium) is an ocular condition in which one iris is a different color from the other iris (complete heterochromia), or where the part of one iris is a different color from the remainder (partial heterochromia or sectoral heterochromia). It is a result of the relative excess or lack of pigment within an iris or part of an iris, which may be inherited or acquired by disease or injury. (Imesch PD, Wallow IH, Albert DM. "The color of the human eye: a review of morphologic correlates and of some conditions that affect iridial pigmentation." Surv Ophthalmol. 1997 Feb; 41 Suppl 2:S117-23. PMID 9154287.) This uncommon condition usually results due to uneven melanin content. A number of causes are responsible, including genetics such as chimerism and Waardenburg syndrome. Trauma and certain medications, such as some prostaglandin analogues can also cause increased or decreased pigmentation in one eye. On occasion, the condition of having two different colored eyes is caused by blood staining the iris after sustaining injury.
British singer David Bowie is a famous person often wrongly attributed with heterochromia. His apparent condition is due to a teenage injury. (One eye appears darker because the pupil is permanently dilated.) American actress Kate Bosworth has sectoral heterochromia, resulting in a hazel section at the bottom of her right blue eye, while the left is completely blue. American Actress Elizabeth Berkley has sectoral heterochromia; her right eye is half green and half brown, and her entire left eye is green. So does actor Anthony Head - he has a patch of hazel in his left eye where both eyes are blue-green overall. The lead vocalist of American band Rise Against, Tim [McIlrath]Create?, has heterochromia; his left eye is blue while his right is brown. American actress Mila Kunis also has heterochromia, resulting in one blue eye and one brown-green eye. American Actress Demi Moore also has heterochromia, by having one green eye, and the other hazel.
References of eye color7:27 PM [Factored from [[References of eye color]]] Anon - 1 changes - 41 hits
Blue eyes are the second most common eye color in the world, although they are very recessive. Blue eyes contain low amounts of melanin within the iris stroma; longer wavelengths of light tend to be absorbed by the underlying iris pigment epithelium, and shorter wavelengths are reflected and undergo Rayleigh scattering. The type of melanin present is eumelanin. The inheritance pattern followed by blue eyes is considered similar to that of a recessive trait, however it is a polygenic trait (meaning that it is controlled by the interactions of several genes, not just one). Eiberg and colleagues showed in a study published in Human Genetics that a Mutation in the 86th intron of the HERC2 Gene, which is hypothesized to interact with the OCA2 Gene promoter, reduced expression of OCA2 with subsequent reduction in melanin production. (Eiberg H, Troelsen J, Nielsen M, Mikkelsen A, Mengel-From J, Kjaer KW, Hansen L. "Blue eye color in human beings may be caused by a perfectly associated founder Mutation in a regulatory element located within the HERC2 ³828³ inhibiting OCA2 expression" Human Genetics 2008 Jan 3. PMID 18172690)
The authors concluded that the Mutation may have arisen in a single individual around the Black Sea region 6,000-10,000 years ago, perhaps suggesting that all people with true blue eyes are more closely related. However, blue eyes with brown spots around the pupil are not related to this Mutation.
Brown eyes are predominant in humans (Eiberg H, Mohr J. "Assignment of genes coding for brown eye color (BEY2) and brown hair colour (HCL3) on [chromosome]Create? 15q." Eur J Hum Genet. 1996;4(4):237-41. PMID 8875191.) and, in many populations, it is (with few exceptions) the only iris color present. (OMIM - SKIN/HAIR/EYE PIGMENTATION, VARIATION IN, 1; SHEP1) It is less common in countries around the Baltic Sea, such as Finland, Estonia and Latvia.
In humans, brown eyes contain large amounts of melanin (melanin) within the iris stroma, which serves to absorb light, particularly at the shorter wavelengths. Brown eyes are the most common eye color, with over half of the world population having them. They are also the most dominant eye colorGene, (Menon IA, Basu PK, Persad S, Avaria M, Felix CC, Kalyanaraman B. "Is there any difference in the photobiological properties of melanins isolated from human blue and brown eyes?" Br J Ophthalmol. 1987 Jul; 71(7):549-52. PMID 2820463.) Very dark brown irises may appear at a glance to be black. (Hammond BR Jr, Fuld K, Snodderly DM. "Iris color and macular pigment optical density." Exp Eye Res. 1996 Mar; 62(3):293-7. PMID 8690039.) (Prieto JG. "Eye color in skin cancer." Int J Dermatol. 1977 Jun; 16(5):406-7. PMID 873674.)
The photographic red-eye effect is more prominent in people with pale (blue, green, or grey) eyes, and a similar effect (possibly the same) is observed in the eyeshine of blue-eyed cats and dogs.
See also:
The appearance of "violet" eyes is thought to occur from the mixing of red and blue reflections. (BBC - h2g2 - Determination of Eye Colour) Some albinos have eyes that appear
violet. Violet eyes are a form of blue eyes, and are just a reflection, pigment, or variant of blue.
Normally, there is a thick layer of melanin on the back of the iris. Even people with the lightest blue eyes, with no melanin on the front of the iris at all, have dark brown coloration on the back of it, to prevent light from scattering around inside the eye. In those with milder forms of [albinism]Create?, the color of the irises is typically blue, but can vary from blue to brown. In severe forms of albinism, there is no pigment on the back of the iris, and light from inside the eye can pass through the iris to the front. In these cases, the only color seen is the red from the hemoglobin of the blood in the capillaries of the iris. Such albinos have pink eyes, as do albino rabbits, mice, or any other animal with total lack of melanin. Transillumination defects can almost always be observed during an eye examination due to lack of iridial pigmentation. (eMedicine - Ocular Manifestations of Albinism : Article by Mohammed O Peracha, MD) The ocular albino also lacks normal amounts of melanin in the retina as well, which allows more light than normal to reflect off the retina and out of the eye. Because of this, the pupillary reflex is much brighter in the albino, and this can increase the red eye effect in photographs.
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Eye color is a polygenic trait and is determined by the amount and type of pigments in the eye's iris. (Wielgus AR, Sarna T. "Melanin in human irides of different color and age of donors." Pigment Cell Res. 2005 Dec; 18(6):454-64. PMID 16280011.) (Prota G, Hu DN, Vincensi MR, [McCormick]Create? SA, Napolitano A. "Characterization of melanins in human irides and cultured uveal melanocytes from eyes of different colors." Exp Eye Res. 1998 Sep;67(3):293-9. PMID 9778410.) Humans and animals have many phenotypic variations in eye color. (Morris, PJ. "Phenotypes and Genotypes for human eye colors." Athro Limited website. Retrieved May 10, 2006.) In humans, these variations in color are attributed to varying ratios of eumelanin produced by melanocytes in the iris. The brightly colored eyes of many bird species are largely determined by other pigments, such as pteridines, purines, and carotenoids. (Oliphant LW. "Pteridines and purines as major pigments of the avian iris." Pigment Cell Res. 1987; 1(2):129-31. PMID 3507666.)
Three main elements within the iris contribute to its color: the melanin content of the iris pigment epithelium, the melanin content within the iris stroma, and the cellular density of the iris stroma. (Huiqiong Wang, Stephen Lin, Xiaopei Liu, Sing Bing Kang. "Separating Reflections in Human Iris Images for Illumination Estimation." Proc. IEEE International Conference on Computer Vision, 2005.) In eyes of all colors, the iris pigment epithelium contains the black pigment, eumelanin. Color variations among different irises are typically attributed to the melanin content within the iris stroma. The density of cells within the stroma affects how much light is absorbed by the underlying pigment epithelium.
Mendelian expression of genes in diploid organisms of trait (biology)
A gene is only a DNA code sequence; the slightly different variations of that sequence are called alleles. Alleles can be significantly different and produce different product RNAs.
Combinations of different alleles thus go on to generate different traits through the information flow charted above. For example, if the alleles on homologous [chromosome]Create?s exhibit a "simple dominance" relationship, the trait of the "dominant" [allele]Create? shows in the phenotype.
See also of trait (biology)7:27 PM [Factored from [[See also of trait (biology)]]] Anon - 2 changes - 62 hits
Genetic origin of traits in diploid organisms of trait (biology)
The heritable unit that may influence a trait is called a gene. A gene is a strand of [DNA]Create? that is part of a very long and compacted string of [DNA]Create? called a [chromosome]Create?. An important reference point along this string is the centromere; the distance from a gene to the centromere is referred to as the gene's [locus]Create? or map location. A chromosomal region known to control a trait while the responsible gene within not being identified is referred to as a [quantitative trait locus]Create?.
The nucleus of a diploid cell contains two of each chromosome, with [homologous]Create? (mostly identical) pairs of chromosomes having the same genes at the same loci.
Biochemistry of dominance and extensions to expression of traits of trait (biology)
The biochemistry of the intermediate proteins determines how they interact in the cell. Therefore, biochemistry predicts how combinations of different alleles will produce varying traits.
Extended expression patterns seen in diploid organisms include facets of incomplete dominance, codominance, and multiple alleles.
A trait is a distinct [phenotypic]Create? character of an organism that may be inherited, environmentally determined or somewhere in between. (Lawrence, Eleanor (2005) Henderson's Dictionary of Biology. Pearson, Prentice Hall. ISBN 0-13-127384-1) For example, eye color is a character, while blue, brown and hazel are traits.
A trait may be any single feature or quantifiable measurement of an organism. However, the most useful traits for genetic analysis are present in different forms in different individuals.
A visible trait is the final product of many molecular and biochemical processes. In most cases, information starts with [DNA]Create? traveling to RNA and finally to protein (ultimately affecting organism structure and function). This is the Central Dogma of molecular biology as stated by Francis Crick.
References of double helix7:27 PM [Factored from [[References of double helix]]] Anon - 1 changes - 44 hits
In geometry a double helix (plural helices) typically consists of two congruent helices with the same axis, differing by a translation along the axis, which may or may not be half-way. ("Double Helix" by Sándor Kabai, The Wolfram Demonstrations Project, 2007.)
In molecular biology, the double helix refers to the structure of [DNA]Create?. The structure of [DNA]Create? was first published in the journal Nature by James D. Watson and Francis Crick in 1953 (
(#1) ) , based upon data from Maurice Wilkins and Rosalind Franklin ( The Structure of the DNA Molecule) . Crick, Wilkins and Watson each received the Nobel Prize for their contributions to the discovery (
References of nucleobase7:27 PM [Factored from [[References of nucleobase]]] Anon - 1 changes - 46 hits
A vast number of nucleobases analogues exist.
The most common application are used as fluorescent probes, either directly or indirectly, such as Aminoallyl nucleotide which are used to label cRNA or cDNA in microarrays.
Structure of nucleobase7:27 PM [Factored from [[Structure of nucleobase]]] Anon - 1 changes - 47 hits
These are incorporated into the growing chain during RNA and/or [DNA]Create? synthesis.
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Notes of Earth7:27 PM [Factored from [[Notes of Earth]]] Anon - 1 changes - 38 hits
Earth's rotation period relative to the Sun—its mean solar day—is 86,400 seconds of mean solar time. Each of these seconds is slightly longer than an SI second because Earth's solar day is now slightly longer than it was during the 19th century due to tidal acceleration. The mean solar second between 1750 and 1892 was chosen in 1895 by Simon Newcomb as the independent unit of time in his Tables of the Sun. These tables were used to calculate the world's ephemerides between 1900 and 1983, so this second became known as the ephemeris second. The SI second was made equal to the ephemeris second in 1967. (
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The Earth's terrain varies greatly from place to place. About 70.8% (
(#49) ) of the surface is covered by water, with much of the continental shelf below sea level. The submerged surface has mountainous features, including a globe-spanning mid-ocean ridge system, as well as undersea volcanoes, oceanic trenches, submarine canyons, oceanic plateaus and abyssal plains. The remaining 29.2% not covered by water consists of mountains, deserts, plains, plateaus, and other geomorphologies.
The Earth's magnetic field is shaped roughly as a magnetic dipole, with the poles currently located proximate to the planet's geographic poles. According to dynamo theory, the field is generated within the molten outer core region where heat creates convection motions of conducting materials, generating electric currents. These in turn produce the Earth's magnetic field. The convection movements in the core are chaotic in nature, and periodically change alignment. This results in field reversals at irregular intervals averaging a few times every million years. The most recent reversal occurred approximately 700,000 years ago. (
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Moon of Earth7:27 PM [Factored from [[Moon of Earth]]] Anon - 1 changes - 42 hits
The abundance of water on Earth's surface is a unique feature that distinguishes the "Blue Planet" from others in the solar system. The Earth's hydrosphere consists chiefly of the oceans, but technically includes all water surfaces in the world, including inland seas, lakes, rivers, and underground waters down to a depth of 2,000 m. The deepest underwater location is Challenger Deep of the Mariana Trench in the Pacific Ocean with a depth of −10,911.4 m. (This is the measurement taken by the vessel Kaikō in March 1995 and is believed to be the most accurate measurement to date. See the Challenger Deep article for more details.) (
(#59) ) The average depth of the oceans is 3,800 m, more than four times the average height of the continents.
The planet's life forms are sometimes said to form a "biosphere". This biosphere is generally believed to have begun evolving about 3.5 billion years ago. Earth is the only place in the universe where life is known to exist. Some scientists believe that Earth-like biospheres might be rare. (
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The Earth's shape is very close to an oblate spheroid—a rounded shape with a bulge around the equator—although the precise shape (the geoid) varies from this by up to 100 meters. (
(#32) ) The average diameter of the reference spheroid is about 12,742 km. More approximately the distance is 40,000 km/π because the meter was originally defined as 1/10,000,000 of the distance from the equator to the north pole through Paris, France. (
The mass of the Earth is approximately 5.98 kg. It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminum (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is believed to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%),
and less than 1% trace elements. (
The atmospheric pressure on the surface of the Earth averages 101.325 kPa, with a scale height of about 8.5 km. It is 78% nitrogen and 21% oxygen, with trace amounts of water vapor, carbon dioxide and other gaseous molecules. The height of the troposphere varies with latitude, ranging between 8 km at the poles to 17 km at the equator, with some variation due to weather and seasonal factors. (
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