دكتورة.م انوار صفار Admin
تاريخ التسجيل : 04/04/2010 البلد /المدينة : bahrain
بطاقة الشخصية المجلة:
| موضوع: الميلانيزيون--سلالة غريبة الالوان!! 12/20/2013, 15:51 | |
|
عدل سابقا من قبل دكتورة.م انوار صفار في 12/20/2013, 18:20 عدل 2 مرات | |
|
بختة المراقب العام المميز
تاريخ التسجيل : 16/04/2010
بطاقة الشخصية المجلة: 50
| موضوع: رد: الميلانيزيون--سلالة غريبة الالوان!! 12/20/2013, 17:09 | |
| الميلانيزيون : وهم السلاله الوحيدة في العالم التي تمتلك بشرة سوداء مع شعر اشقر ويعيشون بجزيرة قرب استراليا شكرا لتعريفنا بسلالة ميلا نيزيون | |
|
بثينة الزعبي المراقب العام المميز
تاريخ التسجيل : 18/02/2012 العمر : 67 البلد /المدينة : النمسا / فيينا
| موضوع: رد: الميلانيزيون--سلالة غريبة الالوان!! 12/20/2013, 23:34 | |
| دراسة مثيرة جدا للاهتمام شكراً لك The study was a classic cases vs. controlsGWAS. They looked at variants in a lot of people with the trait, vs. those without the trait. Additionally, if you check the supplements and read the text it’s obvious there is no population straification. That is,having blonde hair is not correlated with a different ancestry in these Melanesian populations. Rather, this is a relatively robust recessively expressed trait that seems to have been segregating within these groups before contact. Those individuals who are homozygotes tend to have blond hair, while those who are not tend not to have blonde hair. TYRP1 is a pigmentation related locus, so it isn’t surprising that the mutation was around that region of the genome. The key though is to note that the specific mutation is not found in Europeans. Rather, it is limited to Oceanians. The extremely close correspondence between the genotype and the trait, and the lack of similarity in the variants between Europeans and Oceanians, ends debate on questions of the heritability and possible exotic origin of the trait in Oceanians. Now it is known, and the debate shall end.So how did the Oceanians come to have such a high frequency of this trait? Here’s a comment from one of the preeminent biological anthropologists of Melanesia: - اقتباس :
- The mutation, which has no obvious advantages, likely arose by chance in one individual and drifted to a high frequency in the Solomon Islands because the original population was small, says Jonathan Friedlaender, an anthropologist emeritus at Temple University in Philadelphia, Pennsylvania, who was not involved in the study. “This whole area seems to have been populated by very small groups of people making it across these stepping-stone islands, so you do have very dramatic effects in fluctuations of gene frequency.”
عدل سابقا من قبل بثينة الزعبي في 12/21/2013, 04:05 عدل 1 مرات | |
|
فؤاد حسني الزعبي المراقب العام المميز
تاريخ التسجيل : 22/10/2011 العمر : 80 البلد /المدينة : فيينا - النمسا
| موضوع: رد: الميلانيزيون--سلالة غريبة الالوان 12/20/2013, 23:44 | |
| شكرا لك نبذة رائعة وتعريف بهذه السلالة الغريبة وغير المألوفة لدينا | |
|