Inuit live in very cold climates, why do they have dark skin?

Inuit dark skin determined by vitamin D rich diet


Excerpt 1: "But Inuit vitamin D intake wasn’t dependent upon the sun. They get all that they need from their diet, heavy on types of fatty fish that are naturally rich in vitamin D. The plentiful amounts of the vitamin kept them from developing less melanin. In fact, before milk was fortified with D, people living outside of Northern Canada and Alaska loaded their diets with fishy products, such as cod liver oil, to get their daily supplement. So despite their chilly climate and lack of sun exposure, it’s the Inuit diet that has kept them in their natural glow."

https://ghr.nlm.nih.gov/gene/MC1R

Excerpt 2:"The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, which are specialized cells that produce a pigment called melanin. Melanin is the substance that gives skin, hair, and eyes their color. Melanin is also found in the light-sensitive tissue at the back of the eye (the retina), where it plays a role in normal vision.

Melanocytes make two forms of melanin, eumelanin and pheomelanin. The relative amounts of these two pigments help determine the color of a person's hair and skin. People who produce mostly eumelanin tend to have brown or black hair and dark skin that tans easily. Eumelanin also protects skin from damage caused by ultraviolet (UV) radiation in sunlight. People who produce mostly pheomelanin tend to have red or blond hair, freckles, and light-colored skin that tans poorly. Because pheomelanin does not protect skin from UV radiation, people with more pheomelanin have an increased risk of skin damage caused by sun exposure.

The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. When the receptor is activated, it triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin."

My comment: The skin color is determined by epigenetic control of gene expression. Factors influencing the skin color are vitamin D levels in diet and vitamin D production induced by exposure to sunlight. Mutations are not the reason for human skin color variation. We all are the same kind of human beings. There is not such a thing as a human race.

Identical twins can have very different skin, hair or eye colours. Gene sequences don't determine these traits. Population genetics and the evolutionary theory tell serious lies. Don't get misled.

http://www.bionews.org.uk/page_621173.asp

Comments

Post a Comment

Popular posts from this blog

Previous Sexual Partners Can Influence Another Male's Offspring

Image
Telegony (microchimerism) is not studied by pseudoscientists because it refutes the theory of evolution http://www.theneonnettle.com/features/1006-study-women-store-dna-from-every-male-they-have-sex-with "A new study by the University of Seattle and the Fred Hutchinson Cancer Research Center has revealed that Women absorb and retain living DNA of every single man they have sex with. When scientists were trying to determine if women who had been pregnant with a son might be more predisposed to diseases usually found in men, then also found in the study that the female brain also absorbs male DNA." "Le Dantec wrote that some farmer told him that once his swine copulated with a boar and their pigs absolutely resembled the father in color. But when the same swine copulated with another boar some pigs of the second farrow still resembled the color of the male pig the swine had copulated first."   http://modernnotion.com/is-telegony-real/ "Scientists believe the phe...
Read more

Early-stage embryos with abnormalities can still develop into healthy babies

Image
Early-stage embryos with abnormalities can still develop into healthy babies http://www.sanger.ac.uk/news/view/early-stage-embryos-abnormalities-can-still-develop-healthy-babies Excerpt: "Abnormal cells in the early embryo are not necessarily a sign that a baby will be born with a birth defect such as Down’s syndrome, suggests new research from the University of Cambridge, the Wellcome Trust Sanger Institute and the University of Leuven, Belgium. In a study published today (29 March) in the journal Nature Communications, scientists show that abnormal cells are eliminated and replaced by healthy cells, repairing – and in many cases completely fixing – the embryo. Researchers at the Department of Physiology, Development and Neuroscience at Cambridge report a mouse model of aneuploidy, where some cells in the embryo contain an abnormal number of chromosomes. Normally, each cell in the human embryo should contain 23 pairs of chromosomes (22 pairs of chromosomes and one pair of sex chr...
Read more

DNA methylation is directed by RNA

Image
Cellular differentiation, adaptation and variation of organisms is directed by RNA, not DNA https://www.researchgate.net/publication/24312289_RNA-directed_DNA_methylation_and_demethylation_in_plants Excerpt: "RNA-directed DNA methylation (RdDM) is a nuclear process in which small interfering RNAs (siRNAs) direct the cytosine methylation of DNA sequences that are complementary to the siRNAs. In plants, double stranded-RNAs (dsRNAs) generated by RNA-dependent RNA polymerase 2 (RDR2) serve as precursors for Dicer-like 3 dependent biogenesis of 24-nt siRNAs. Plant specific RNA polymerase IV (Pol IV) is presumed to generate the initial RNA transcripts that are substrates for RDR2. siRNAs are loaded onto an argonaute4-containing RISC (RNA-induced silencing complex) that targets the de novo DNA methyltransferase DRM2 to RdDM target loci." My comment: There are only a few chemical modifications discovered on the DNA and histones; especially methylation and acetylation. But the list o...
Read more