Khan Naazneen, Chittoria Anita, Pande Veena, Jaiswal Yogesh Kumar, Das Aparup
Evolutionary Genomics and Bioinformatics Laboratory, Division of Genomics and Bioinformatics, National Institute of Malaria Research, Sector 8, Dwarka, New Delhi - 110077, India.
Ann Hum Biol. 2012 Jul;39(4):281-9. doi: 10.3109/03014460.2012.689326. Epub 2012 Jun 1.
It has now been well documented that the type (coding, non-coding) and location (nuclear, mitochondrial etc.) of genetic markers heavily influence evolutionary inferences; realistic assumptions can be drawn if multiple putatively neutral DNA fragments spread across the genome are used.
To infer human population history, Single Nucleotide Polymorphisms (SNPs), located in the non-coding regions of different genes in the X-chromosome have been developed as 'putatively neutral markers'.
A population sample consisting of 16 male individuals from the western part of India was utilized for sequencing eight DNA fragments located in introns of three genes (Duchenne muscular dystrophy, Factor IX and Pyruvate dehydrogenase E1 sub-unit) on the human X-chromosome. PCR amplification and DNA sequencing confirmed the polymorphic status of all the fragments.
Twenty nine SNPs were found to be segregating in the Western Indian population samples. Using these SNPs the nucleotide diversity and demographic parameters of the Western Indian population were estimated. Several tests of neutrality ascertained that all eight fragments evolve putatively neutrally. Further, linkage disequilibrium analyses confirmed this fact.
All eight DNA fragments seem to bear the characteristics to be considered as 'putatively neutral genetic markers' and thus, could be utilized for inference of human population and demographic histories.
现已充分证明，遗传标记的类型（编码、非编码）和位置（核、线粒体等）对进化推断有重大影响；如果使用遍布基因组的多个假定中性的DNA片段，就可以得出现实的假设。
为推断人类群体历史，位于X染色体不同基因非编码区的单核苷酸多态性（SNP）已被开发为“假定中性标记”。
利用来自印度西部的16名男性个体组成的群体样本，对位于人类X染色体上三个基因（杜氏肌营养不良症、凝血因子IX和丙酮酸脱氢酶E1亚基）内含子中的八个DNA片段进行测序。PCR扩增和DNA测序证实了所有片段的多态性状态。
在印度西部群体样本中发现29个SNP处于分离状态。利用这些SNP估计了印度西部群体的核苷酸多样性和人口统计学参数。多项中性检验确定所有八个片段均以假定中性方式进化。此外，连锁不平衡分析证实了这一事实。
所有八个DNA片段似乎都具有被视为“假定中性遗传标记”的特征，因此可用于推断人类群体和人口历史。
