冒白髮心慌慌 科學家揪關鍵基因 時間：2016-03-02 19:41 新聞引據：中央社路透社報導，研究人員1日表示，分析拉丁美洲5國超過6,300人的DNA後，他們找出可能讓人長出灰白頭髮的基因IRF4。IRF4攸關調節黑色素，黑色素與髮色、皮膚和眼睛的色澤有關係。研究人員之一、倫敦大學學院(University College London)人類遺傳學家林納瑞斯(Andres Ruiz-Linares)表示，擁有這種基因的人比較可能出現白頭髮。這項研究結果發表於「自然通訊」(Nature Communications)期刊。研究人員並說，頭髮變白不只是遺傳，其他原因還包括壓力或經歷創傷事件。倫敦大學學院統計遺傳學家艾德希卡里(Kaustubh Adhikari)表示：「這確實是針對人類頭髮變白所做的首項遺傳學研究。」
A genome-wide association scan in admixed Latin Americans identifies loci influencing facial and scalp hair features, Nature Communications 7, Article number: 10815 doi:10.1038/ncomms10815, We report a genome-wide association scan in over 6,000 Latin Americans for features of scalp hair (shape, colour, greying, balding) and facial hair (beard thickness, monobrow, eyebrow thickness). We found 18 signals of association reaching genome-wide significance (P values 5 × 10−8 to 3 × 10−119), including 10 novel associations. These include novel loci for scalp hair shape and balding, and the first reported loci for hair greying, monobrow, eyebrow and beard thickness. A newly identified locus influencing hair shape includes a Q30R substitution in the Protease Serine S1 family member 53 (PRSS53). We demonstrate that this enzyme is highly expressed in the hair follicle, especially the inner root sheath, and that the Q30R substitution affects enzyme processing and secretion. The genome regions associated with hair features are enriched for signals of selection, consistent with proposals regarding the evolution of human hair.
Researchers Identify Gene for Gray Hair: IRF4 Mar 1, 2016 by Editors, The first gene identified for graying hair has been discovered by an international team of researchers. At the top are shown drawings illustrating the seven hair features examined in this study; thick lines connect these features with the candidate genes identified in regions with single-nucleotide polymorphisms (SNPs) reaching genome-wide significant association. At the bottom is shown a composite Manhattan plot displaying all significantly associated SNPs for the hair features examined; the rs number of the SNP with the smallest P value is shown at the top of each association peak. At the top are shown drawings illustrating the seven hair features examined in this study; thick lines connect these features with the candidate genes identified in regions with single-nucleotide polymorphisms (SNPs) reaching genome-wide significant association. At the bottom is shown a composite Manhattan plot displaying all significantly associated SNPs for the hair features examined; the rs number of the SNP with the smallest P value is shown at the top of each association peak. The team, led by Prof. Andres Ruiz-Linares of University College London, analyzed a population of 6,630 people with varied ancestry across Latin America to identify new genes associated with hair color, graying, density and shape, i.e. straight or curly. "Our study sample consists of 6,630 volunteers from the CANDELA cohort recruited in five Latin American countries (Brazil, Colombia, Chile, Mexico and Peru)," Prof. Ruiz-Linares and co-authors said."In these individuals, we performed a categorical assessment (in men and women) of: scalp hair shape (curliness), color, balding and graying as well as (in men) of beard thickness (that is, density), monobrow and eyebrow thickness." The gene identified for gray hair, IRF4 (interferon regulatory factor 4 gene), is known to play a role in hair color but this is the first time it has been associated with the graying of hair."IRF4 is involved in regulating production and storage of melanin, the pigment that determines hair, skin and eye color," the scientists said."Hair graying is caused by an absence of melanin in hair so the scientists want to find out IRF4's role in this process." Understanding how this gene influences hair graying could help the development of new cosmetic applications that change the appearance of hair as it grows in the follicle by slowing or blocking the graying of hair."We have found the first genetic association to hair graying, which could provide a good model to understand aspects of the biology of human aging," Prof. Ruiz-Linares said. "Understanding the mechanism of the IRF4 graying association could also be relevant for developing ways to delay hair graying." The team found additional genes associated with hair including EDAR (ectodysplasin A receptor) for beard thickness and hair shape, PRSS53 (protease serine S1 family member 53) for hair curliness, FOXL2 (forkhead box L2) for eyebrow thickness, and PAX3 (paired box gene 3) for monobrow prevalence."It has long been speculated that hair features could have been influenced by some form of selection, such as natural or sexual selection, and we found statistical evidence in the genome supporting that view," said team member Dr. Kaustubh Adhikari, also of University College London."The genes we have identified are unlikely to work in isolation to cause graying or straight hair, or thick eyebrows, but have a role to play along with many other factors yet to be identified."
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