Gametic products transmitted by chickens heterozygous for chromosomal rearrangements

Chromosomal analysis was made from 3744 chick embryos derived from reciprocal matings between parents, one of which was heterozygous for a pericentric inversion, a centric fission, or one of three translocations. The objectives were to determine the types and frequencies of genetically balanced and unbalanced gametes transmitted to early embryos by rearrangement heterozygotes and to ascertain if some gametic types were preferentially produced or utilized. The array of embryos obtained from the heterozygous sires did not deviate significantly from the expected, except in the case of the centric fission group. Among embryos derived from heterozygous dams, however, significant deviations from the expected 1:1 ratio for complementary gametic products, resulting from specific balanced and unbalanced segregation types, were found consistently in all three translocation groups and the centric fission group (P less than 0.025). It was concluded that differences exist between heterozygous sires and dams in the frequencies at which some gametic types are produced. The deviations from the expected ratios among progeny of heterozygous dams may be the result of anaphase lagging during the meiotic division of oogenesis.