Krackow S, Gruber F
Universität Konstanz, Fakultät für Biologie, Federal Republic of Germany.
Lab Anim. 1990 Oct;24(4):345-52. doi: 10.1258/002367790780865895.
Breeding records from three inbred strains of mice (BALB/c ABom, C57BL/10ScSn, C3H/He/Kon) were examined with respect to the effects of parity and mode of conception upon litter size and sex ratio at birth. Litters from 3 modes of conception were considered: litters of primipares, litters of multipares conceived during postpartum oestrus and litters conceived after lactational anoestrus. Litters of multipares were assigned to one of these latter groups according to the inter-litter intervals. Parity had no significant effect upon the sex ratio but had a significant one upon the litter size, which did not vary between the strains when first litters were excluded from analysis. The expected variations in response to the mode of conception were found in BALB/c ABom mice but both the effects on the litter size as well as on the sex ratio varied significantly between the strains. Litter size reduction per se could be ruled out to be the cause of the sex ratio variations found. Rather, it is suggested that sex-specificity of embryonic loss depends upon the mode of conception.
对三种近交系小鼠（BALB/c ABom、C57BL/10ScSn、C3H/He/Kon）的繁殖记录进行了检查，以研究胎次和受孕方式对产仔数和出生时性别比例的影响。研究了三种受孕方式的窝仔：初产雌鼠的窝仔、产后发情期受孕的经产雌鼠的窝仔以及哺乳期无发情期后受孕的窝仔。经产雌鼠的窝仔根据窝间距被分配到后两组中的一组。胎次对性别比例没有显著影响，但对产仔数有显著影响，当排除第一胎进行分析时，各品系间产仔数没有差异。在BALB/c ABom小鼠中发现了对受孕方式预期的反应变化，但各品系间对产仔数和性别比例的影响均有显著差异。可以排除产仔数减少本身是所发现的性别比例变化的原因。相反，有人认为胚胎损失的性别特异性取决于受孕方式。
