Frances E Clayton

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Species formation is usually accompanied by chromosomal reorganization. Thus, even very closely related species frequently differ in chromosome number (polyploidy, aneuploidy, centric increase or decrease) or in gene sequence (inversions, centric shifts, translocations). The question arises whether such karyotypic changes are incidental or whether there is(More)
The mitotic and meiotic chromosomes of Drosophila grimshawi and Drosophila cyrtoloma, species of the picture-wing group of Hawaiian Drosophilidae, are described. The "primitive" Drosophila karyotype of five pairs of rods and one pair of dots, found in grimshawi, is compared with the karyotype for cyrtoloma, which consists of five pairs of V-shaped and one(More)
URING the first two decades following MULLER'S (1927) proof that D irradiation induced genetic changes, most of the effect was considered to result from ionizations (and excitations) within the chromosome itself. LEA (1946) interpreted the evidences accumulated up to that time as indicating that most genetic damage was induced directly, although he believed(More)
NE method of studying the pleiotropic actions of a gene, as expressed in 0 various phenotypic effects in the adults, is the analysis of gene effects in a multiple allelic series. One group of such mutants which has been analyzed extensively by a number of different methods is the lozenge series of pseudoalleles in Drosophila melanogaster. One of the(More)
N the investigation of pigmentation among the lozenge series of pseudoalleles I in Drosophila melanogaster, the amount and distribution of red and brown pigments in the compound eyes of the lozenge mutants can be analyzed histologically by studying the genic effect on the two pigments separately. In an earlier report (CLAYTON 1957), the distribution of(More)