Among the approximately 60 species of the lizard genus Sceloporus, there is much karyotypic diversity, resulting primarily from the fixation of "Robertsonian rearrangements" (centric fusions and fissions; Hsu and Mead, 1969; Jackson, 1971). Diploid (2n) chromosome numbers vary from 22 to 46 (Cole, 1970, 1971; Hall, 1973), a range exceeding that known for any other lizard genus. Because comparab...

Drug-resistant mutants of somatic cell lines fall into two classes: one seems to correspond to classical gene mutation, the other is characterized, albeit transiently, by karyotypic instability, high reversion frequency, and low plating efficiency. An interpretation of the origin of these drug-resistant mutants is offered on the basis of chromosomal variation, which generates variation of the n...

Evidence is provided which shows that there is a wider variation in karyotypes of Rosa acicularis subspecies seen within their ranges in North America (Rosa acicularis Lindl. subsp. sayi (Schwein.) W.H. Lewis and the Eurasian species (Rosa acicularis Lindl. subsp. acicularis) than was originally presumed. It is proposed that the evolution and distribution of these karyotypes into two distinct s...

We used spectral karyotyping to provide a detailed analysis of karyotypic aberrations in the diverse group of cancer cell lines established by the National Cancer Institute for the purpose of anticancer drug discovery. Along with the karyotypic description of these cell lines we defined and studied karyotypic complexity and heterogeneity (metaphase-to-metaphase variations) based on three separa...

Acledra comprises 15 taxonomically identified species, most of which are crop pests. This is the first cytogenetic study of species of this genus. Acledra kinbergii and A. modesta showed the modal number of the Pentatomidae (2n = 14 = 12 + XY), while A. bonariensis had a reduced complement (2n = 12 = 10 + XY), with a markedly larger autosomal pair. Meiotic behavior follows the general pattern o...

Drosophila melanogaster Meigen, 1830 has served as a model insect for over a century. Sequencing of the 11 additional Drosophila Fallen, 1823 species marks substantial progress in comparative genomics of this genus. By comparison, practically nothing is known about the genome size or genome sequences of parasitic wasps of Drosophila. Here, we present the first comparative analysis of genome siz...