THE GENETICS OF A TOOTH DEFECT IN THE MOUSE
THE GENETICS OF A TOOTH DEFECT IN THE MOUSE
复制标题
DOI：
10.1098/rspb.1951.0034
复制
发表时间：
1951-01-01
期刊：
影响因子：
--
通讯作者：
GRUNEBERG, H
中科院分区：
文献类型：
--
作者：
GRUNEBERG, H
在CBA纯系小鼠中，17.9%的小鼠出现第三磨牙缺失，但在C57黑色品系小鼠中未见第三磨牙缺失。在这些品系间的正反交中，该性状在F_1代为隐性，而在402F_2小鼠或F_1CBA正反交共460只动物中则完全没有恢复。这种明显的“非孟德尔式”行为是由以下因素共同作用造成的。虽然C57 Black的第三颗磨牙相当大，但CBA的第三颗磨牙很小，大小非常可变，而且系列中(潜在的)最小的成员往往完全不存在。CBA和C57 Black之间第三颗磨牙大小的差异是多因素的，较大的磨牙相对于较小的磨牙是“显性的”F1，在小鼠中，第三磨牙的大小通常会随着怀孕的不同母亲的情况而变化；虽然在第三磨牙大的情况下这不会产生进一步的后果，但它会导致在某些CBA幼鼠中显著地非随机地出现缺失磨牙的动物。第三颗磨牙的大小也取决于母亲的‘活力’，近亲交配的妈妈的年轻宝宝的牙齿比杂交妈妈的年轻宝宝(F2)要小。这导致‘杂交活力’在F2中比在F2中延迟出现。在F_1、F_2和回交♂×F_1♀中，这些变量导致了大小分布，其中根本不会出现CBA分布中较小的牙齿大小。在正反交(F1♂×Cba♀)中，如果检测一个非常大的样本，可能会恢复‘缺失磨牙’的性状。
Absence of third molars occurs in 17.9% of the mice of the CBA pure line, but has not been encountered in the C57 Black strain. In reciprocal crosses between these lines, the character was recessive inF1, but it was not recovered at all in 402F2mice or in reciprocal backcrosses ofF1CBA totalling 460 animals. This apparently 'un-Mendelian’ behaviour is brought about by the combined action of the following factors. While C57 Black has fairly large third molars, those of CBA are small and very variable in size, and the (potentially) smallest members of the series tend to be absent altogether. The difference in third molar size between CBA and C57 Black is multifactorial, large size being ‘dominant’ over small sizeF1, In mice generally, the size of the third molars varies with maternal conditions which may change from pregnancy to pregnancy; while this has no further consequences where third molars are large, it leads to strikingly non-random occurrence of animals with absent molars in certain CBA littefs. Third molar size also depends on the ‘vigour’ of the mother, young bom of inbred mothers having smaller teeth than young bom of hybrid mothers (F2).This leads to a delayed appearance of ‘hybrid vigour’ as to third molar size inF2rather than inF2. In combination, these variables give rise to size distributions inF1,F2and the backcross CBA ♂ xF1♀ in which the smaller tooth sizes of the CBA distribution do not occur at all. In the reciprocal backcross (F1♂ x CBA ♀), the character ‘absent molars’ might be recovered if a very large sample were examined.