Jurka Jerzy, Krnjajic Milovan, Kapitonov Vladimir V, Stenger Judith E, Kokhanyy Oleksiy
Genetic Information Research Institute, Mountain View, California 94043, USA.
Theor Popul Biol. 2002 Jun;61(4):519-30. doi: 10.1006/tpbi.2002.1602.
Repetitive elements are distributed non-randomly in the human genome but, as reviewed in this paper, biological processes underlying the observed patterns appear to be complex and remain relatively obscure. Recent findings indicate that chromosomal distribution of Alu retroelements deposited in the past is different from the distribution of Alu elements that continue to be inserted in human population. These active elements from AluY sub(sub)families are the major focus of this paper. In particular, we analyzed chromosomal proportions of 19 AluY subfamilies, of which nine are reported for the first time in this paper. These 19 subfamilies contain over 80% of Alu elements that are polymorphic in the human genome. The chromosomal density of these most recent Alu insertions is around three times higher on chromosome Y than on chromosome X and over two times higher than the average density for all human autosomes. Based on this observation and other data we propose that active Alu elements are passed through paternal germlines. There is also some evidence that a small fraction of active Alu elements from less abundant subfamilies can be retroposed in female germlines or in the early embryos. Finally, we propose that the origin of Alu subfamilies in human populations may be related to evolution of chromosome Y.
重复元件在人类基因组中呈非随机分布，但正如本文所综述的，观察到的模式背后的生物学过程似乎很复杂，仍相对模糊。最近的研究结果表明，过去沉积的Alu逆转录元件的染色体分布与仍在人类群体中插入的Alu元件的分布不同。来自AluY亚家族的这些活跃元件是本文的主要研究重点。特别是，我们分析了19个AluY亚家族的染色体比例，其中9个是本文首次报道。这19个亚家族包含了人类基因组中超过80%的多态性Alu元件。这些最新Alu插入的染色体密度在Y染色体上比在X染色体上高约三倍，比所有人类常染色体的平均密度高两倍多。基于这一观察结果和其他数据，我们提出活跃的Alu元件是通过父系种系传递的。也有一些证据表明，来自较少丰富亚家族的一小部分活跃Alu元件可以在雌性种系或早期胚胎中逆转录。最后，我们提出人类群体中Alu亚家族的起源可能与Y染色体的进化有关。
