Peripato Andréa C, Cheverud James M
Department of Biology/Genetics, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP 05508-900, Brazil.
Am Nat. 2002 Dec;160 Suppl 6:S173-85. doi: 10.1086/342900.
The basis of social evolution in mammals is the mother-offspring relationship. It is also the primary and most important instance of indirect genetic effects, where genetic variation in one individual affects phenotypic variation among others. This relationship is so important in mammals that often the major factor determining the life or death of newborns is the environment provided by their mother. Variations in these environments can be due to variations in maternal genotypes. In our work with the intercross of two mouse inbred strains, LG/J and SM/J, we uncovered a very severe variation in maternal performance. These females failed to nurture their offspring and showed abnormal maternal behaviors leading to loss of their litter. Rather than this being due to a single gene variant as in knockout mice, we uncovered a complex genetic basis for this trait. The effects of genes on maternal performance are entirely context dependent in our cross. They depend on the alleles present at the same or other epistatically interacting loci. Genomic locations identified in this study include locations of candidate genes whose knockouts displayed similar aberrant maternal behavior. Behaviors significantly associated with maternal performance in this study include suckling, nest building, placentophagia, pup grooming, and retrieval of pups after disturbance.
哺乳动物社会进化的基础是母婴关系。它也是间接遗传效应的主要且最重要的实例，即一个个体的遗传变异会影响其他个体的表型变异。这种关系在哺乳动物中非常重要，以至于通常决定新生儿生死的主要因素是其母亲提供的环境。这些环境的变化可能归因于母本基因型的变化。在我们对两个小鼠近交系LG/J和SM/J进行杂交的研究中，我们发现母本表现存在非常严重的变异。这些雌鼠无法哺育后代，并表现出异常的母性行为，导致幼崽死亡。与基因敲除小鼠不同，这并非由单一基因变异所致，我们发现了这一性状的复杂遗传基础。在我们的杂交实验中，基因对母本表现的影响完全取决于背景。它们取决于同一或其他上位相互作用位点上存在的等位基因。本研究中确定的基因组位置包括那些基因敲除后表现出类似异常母性行为的候选基因的位置。本研究中与母本表现显著相关的行为包括哺乳、筑巢、食胎盘、舔舐幼崽以及在幼崽受到干扰后找回它们。
