Chromosomal and embryological analyses of nuclear changes occurring in embryos derived from transfers of nuclei between Rana pipiens and Rana sylvatica.

摘要: Abstract Diploid nuclei from normal blastulae of Rana pipiens were transplanted into enucleated eggs sylvatica. Following 10–12 divisions in the foreign cytoplasm, their nuclear descendants transferred back eggs. All but one embryos derived these developed abnormally and arrested at various stages ranging late to young tadpoles. These results, like those obtained by Moore, 1958a , 1958b 1960 demonstrate that are changed as a consequence replicating sylvatica cytoplasm no longer capable promoting development when returned own type cytoplasm. The main objective this investigation was determine whether restrictions developmental capacity involve cytologically detectable alterations chromosome complement. Analysis metaphase plates developing back-transfer showed all did fact possess abnormal numbers types chromosomes follows: 1. chromosomal abnormalities most pronounced arresting early (gastrulae, neurulae, tailbud embryos). When compared with karyotype, complements found following abnormalities: (a) gains losses four chromosomes, (b) ring minute case, acentric fragments, (c) decrease number large coupled an increase small ones. karyotypes so it not possible specify which involved rearrangements. 2. later (late tadpoles) less extensive consequently could be analyzed greater detail. aneuploid or two and, unlike more deficient described above, rings minutes. A detailed karyotype analysis clone revealed lacked specific known present diploid set same time, possessed new structural normally pipiens. Some appeared result translocation involving distinctive (no. 10) Karyotypic just can account for changes results Moore (1960) show irreversible. According evidence presented report, arise during time dividing exactly how they produced remains worked out.