Rikke B A, Zhao Y, Daggett L P, Reyes R, Hardies S C
Department of Biochemistry, University of Texas Health Science Center at San Antonio 78284-7760, USA.
Genetics. 1995 Feb;139(2):901-6. doi: 10.1093/genetics/139.2.901.
The inbred mouse strain, C57BL/6J, was derived from mice of the Mus musculus complex. C57BL/6J can be crossed in the laboratory with a closely related mouse species, M. spretus to produce fertile offspring; however there has been no previous evidence of gene flow between M. spretus and M. musculus in nature. Analysis of the repetitive sequence LINE-1, using both direct sequence analysis and genomic Southern blot hybridization to species-specific LINE-1 hybridization probes, demonstrates the presence of LINE-1 elements in C57BL/6J that were derived from the species M. spretus. These spretus-like LINE-1 elements in C57BL/6J reveal a cross to M. spretus somewhere in the history of C57BL/6J. It is unclear if the spretus-like LINE-1 elements are still embedded in flanking DNA derived from M. spretus or if they have transposed to new sites. The number of spretus-like elements detected suggests a maximum of 6.5% of the C57BL/6J genome may be derived from M. spretus.
近交系小鼠C57BL/6J源自小家鼠复合体的小鼠。C57BL/6J在实验室中可与亲缘关系密切的小鼠物种西班牙小鼠杂交，产生可育后代；然而，此前在自然界中没有西班牙小鼠和小家鼠之间基因流动的证据。利用直接序列分析和针对物种特异性LINE-1杂交探针的基因组Southern印迹杂交对重复序列LINE-1进行分析，结果表明C57BL/6J中存在源自西班牙小鼠物种的LINE-1元件。C57BL/6J中这些类似西班牙小鼠的LINE-1元件揭示了在C57BL/6J的历史上某个地方与西班牙小鼠有过杂交。目前尚不清楚类似西班牙小鼠的LINE-1元件是否仍嵌入源自西班牙小鼠的侧翼DNA中，或者它们是否已转座到新的位点。检测到的类似西班牙小鼠元件的数量表明，C57BL/6J基因组中最多6.5%可能源自西班牙小鼠。
