Department of Anatomy Pharmacology and Legal Medicine, University of Turin, Italy.
Forensic Sci Int Genet. 2011 Mar;5(2):152-4. doi: 10.1016/j.fsigen.2010.10.012. Epub 2010 Nov 18.
Twenty X-chromosomal short tandem repeat (STR) loci were typed in 80 families of Italian descent, composed by mother and two or more sons, for a total of 93 meiosis. The analyzed X-STR panel included six clusters of closely linked markers (each spanning<3cM): DXS10135-DXS10148-DXS8378 (Xp22); DXS7132-DXS10074-DXS10079 (Xq12); DXS6801-DXS6809-DXS6789 (Xq21); DXS7424-DXS101 (Xq22); DXS10103-HPRTB-DXS10101 (Xq26); DXS8377-DXS10134-DXS7423-DXS10146 (Xq28). Recombination fractions between pairs of markers calculated by pedigree analysis were compared with those obtained from the second-generation Rutgers combined linkage-physical map of the human genome. The observed differences confirm that recombination is not homogeneous along the X chromosome and that the conventional subdivision of X-STRs in four groups of completely unlinked markers cannot be regarded as true. Significant linkage disequilibrium was found between markers DXS6801 and DXS6809 (p=0.017). The effect on likelihood calculations of inferring haplotype frequencies from allele distributions rather than haplotype count in the relevant population was evaluated.
对 80 个意大利裔家庭的 93 次减数分裂进行了 20 个 X 染色体短串联重复（STR）基因座的分型，这些家庭由母亲和两个或更多的儿子组成。分析的 X-STR 面板包括六个紧密连锁的标记簇（每个跨越<3cM）：DXS10135-DXS10148-DXS8378（Xp22）；DXS7132-DXS10074-DXS10079（Xq12）；DXS6801-DXS6809-DXS6789（Xq21）；DXS7424-DXS101（Xq22）；DXS10103-HPRTB-DXS10101（Xq26）；DXS8377-DXS10134-DXS7423-DXS10146（Xq28）。通过系谱分析计算的标记对之间的重组分数与从第二代罗格斯人类基因组联合连锁物理图谱获得的分数进行了比较。观察到的差异证实，重组在 X 染色体上不是均匀的，并且不能将 X-STR 分为四个完全不连锁的标记组视为真实的。标记 DXS6801 和 DXS6809 之间存在显著的连锁不平衡（p=0.017）。评估了从相关群体的等位基因分布而不是单倍型计数推断单倍型频率对似然计算的影响。
