小鼠t单倍型的进化：近期在全球范围内渗入小家鼠。
Evolution of the mouse t haplotype: recent and worldwide introgression to Mus musculus.
作者信息
Morita T, Kubota H, Murata K, Nozaki M, Delarbre C, Willison K, Satta Y, Sakaizumi M, Takahata N, Gachelin G
机构信息
Department of Microbial Genetics, Osaka University, Japan.
出版信息
Proc Natl Acad Sci U S A. 1992 Aug 1;89(15):6851-5. doi: 10.1073/pnas.89.15.6851.
Mouse t haplotypes are variants of chromosome 17, consisting of four inversions. Despite the homozygous lethality and pleiotropic effect on embryonic development, sperm production, and recombination, they have widely spread in natural populations of the house mouse (10-40% in frequency) because of the meiotic drive advantage. We sequenced 14 Tcp-1 (t-complex polypeptide 1) genes from four t haplotypes, nine wild mice, and a rat as a reference. From a comparison of intron sequences of 610 base pairs, we dated the origin of t haplotypes to 2.9 +/- 0.7 million years ago, which predates the splitting of Mus musculus subspecies (approximately 1 million years ago). However, the Tcp-1 intron sequences of t haplotypes from different M. musculus subspecies from various parts of the world show no divergence, indicating the recent introgression (no earlier than 0.8 million years ago) of a single ancestral type. Nucleotide changes in coding regions are also consistent with this conclusion. Hence, polymorphisms among t haplotypes including lethality factors have accumulated during this short time period independently in each M. musculus subspecies.
小鼠t单倍型是17号染色体的变体，由四个倒位组成。尽管对胚胎发育、精子生成和重组具有纯合致死性和多效性影响，但由于减数分裂驱动优势，它们在小家鼠的自然种群中广泛传播（频率为10%-40%）。我们对来自四种t单倍型、九只野生小鼠的14个Tcp-1（t-复合体多肽1）基因进行了测序，并以一只大鼠作为参考。通过对610个碱基对的内含子序列进行比较，我们将t单倍型的起源追溯到290±70万年前，这早于小家鼠亚种的分化（约100万年前）。然而，来自世界各地不同小家鼠亚种的t单倍型的Tcp-1内含子序列没有差异，表明单一祖先类型是最近渗入的（不早于80万年前）。编码区的核苷酸变化也与这一结论一致。因此，包括致死因子在内的t单倍型之间的多态性在这个短时间内于每个小家鼠亚种中独立积累。
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