THE TESTIS-DETERMINING AUTOSOMAL TRAIT, TDA-1, OF C57BL/6J IS DETERMINED BY MORE THAN A SINGLE AUTOSOMAL GENE WHEN COMPARED WITH DBA/2J MICE
THE TESTIS-DETERMINING AUTOSOMAL TRAIT, TDA-1, OF C57BL/6J IS DETERMINED BY MORE THAN A SINGLE AUTOSOMAL GENE WHEN COMPARED WITH DBA/2J MICE
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作者：
BIDDLE, FG;EISNER, JR;EALES, BA
C57BL/6J小鼠品系的TDA-1或决定睾丸的常染色体性状是通过回交配对将家鼠的Y染色体导入C57BL/6J小鼠而引起注意的。在具有pochiavinus Y染色体的XY个体中，F-1代表现出正常的睾丸发育。在回交和随后与C57BL/6J雌性的杂交中，XY个体表达双侧卵巢或卵巢与对侧卵巢或睾丸或双侧卵巢的各种组合，少数个体具有双侧卵巢。以前的一些育种数据似乎支持这样的假设，即C57BL/6J具有不同于poschiavinus品系的常染色体隐性因子，在纯合状态下，导致poschiavinus Y染色体的睾丸发育不完全。随后使用重组近交系方法定位TDA-1因子的尝试未能定位TDA-1，这表明它可能映射到不同的染色体上，这取决于使用的菌株对。我们构建了两株与Poschiavinus Y染色体同源的C57BL/6J和DBA/2J菌株。在C57BL/6J.Y-POS同源品系中，表现睾丸发育不全的倾向呈正态分布，发育中的阈值指定了卵巢、卵巢和睾丸不同类别组合的概率(或正态分布下的面积)。DBA/2J.Y-POS同源品系睾丸发育正常。用这两个同源品系和它们的正常亲本品系进行标准杂交，检测了C57BL/6J品系的正反交F-1代和四种回交世代，其中所有XY个体都具有Phichiavinus Y染色体。C57BL/6J的TDA-1性状对DBA/2J是隐性的，但分离回交世代拒绝单基因模式。
The putative Tda-1 or testis-determining autosomal trait of the C57BL/6J mouse strain came to attention when the Y chromosome from the poschiavinus variety of Mus musculus domesticus was introduced into C57BL/6J by backcross matings. The F-1 generation expressed normal testis development in XY individuals with the poschiavinus Y chromosome. In the backcross and subsequent crosses to C57BL/6J females, XY individuals expressed ovaries bilaterally or various combinations of an ovotestis with a contralateral ovary or testis or bilateral ovotestes and a few had testes bilaterally. Some of the previous breeding data appeared to support the hypothesis that C57BL/6J had an autosomal recessive factor that differed from the poschiavinus strain and, in the homozygous state, caused incomplete testis development with the poschiavinus Y chromosome. Subsequent attempts to map the Tda-1 factor, using a recombinant inbred strain approach, failed to localize Tda-1 and this suggests it might map to different chromosomes depending on which strain pairs are used. We constructed two strains of C57BL/6J and DBA/2J that are congenic for the poschiavinus Y chromsome. In the C57BL/6J.Y-POS congenic strain, liability to express incomplete testis development is normally distributed and thresholds in development specify the probability (or areas under the normal distribution) of different classes of ovary, ovotestis, and testis combinations. Testis development is normal in the DBA/2J.Y-POS congenic strain. With the two congenic strains and their normal parental strains we were able to conduct standard crosses to examine the reciprocal F-1 and four types of backcross generations to the C57BL/6J strain in which all XY individuals have the poschiavinus Y chromosome. The Tda-1 trait of C57BL/6J is recessive to DBA/2J, but the segregating backcross generations reject the single gene model.