Metaphase chromosome configuration of the immigrans species group of Drosophila.

Abstract

Metaphase chromosome configurations of 23 species and subspecies belonging to five subgroups of the immigrans species group of Drosophila were examined by the Giemsa staining method, from the point of view of the phylogenetic relationships in this species group.New to science are the descriptions of the karyotypes of five species, Taxon-C, Taxon-F, D, nivei f rons,, D. quadrilineata and D, neohypocausta which are 2n=8, 2R+1V+1D; 2n=8, 2R+1V+1D; 2n=8, 2R+1V+1D; 2n =12, 4R+ 1V+ 1D; and 2n = 6, 2R+ 1V, respectively.The karyotypes of the other species were also examined and compared with earlier descriptions. Some of our observations agreed with earlier ones but the remainder showed some major or minor differences from the previous reports.The basic karyotype of the species belonging to the immigrans species group was 2n=8, 2R+1V+1D (or short rod). The karyotypes of D. annul ipes and D. quadrilineata of the D. quadrilineata subgroup, of D, argentostriata and D, silvistriata of the D, lineosa subgroup and of D, neohypocausta of the D. hypocausta subgroup differed fundamentally from the basic type of the immigrans species group. These five species might be somewhat remote from the other species of the immigrans group.Some species exhibited intraspecific variations among the forms of the Y chromosome and Chromosome 4, with additional heterochromatin.In the D. nasuta subgroup, it seemed that fusions were important factors in their evolution. D, albomicans is the most advanced species, and from considerations of morphological similarities, results of hybridization tests, karyotypes, and geographical distribution, D, nasuta is the most plausible species from which D, albomicans originated. D, albomicans collected from the Chiangmai population in Thailand had supernumerary chromosomes, the most peculiar phenomenon among the karyotype variations of the immigrans species group. These chromosomes may be maintained consistently in this population.

Incipient reproductive isolation between Drosophila nasuta and Drosophila albomicans

“…However, there is a striking difference in karyotypes between the two. The basic karyotype of this group is 1V + 2R + 1D (ie, 2n = 8), yet from among all members of this group, only D albomicans has 2V + 1D (2n = 6), a result of fusions of the third and the sex chromosomes (Wakahama and Kitagawa, 1972;Wakahama et al, 1983). …”

“…David and Tsacas (1981) (Wilson et al, 1969;Wakahama et al, 1983;Hatsumi, 1987 (Inoue and Kitagawa, 1974;1975) …”

Cold tolerance and metabolic rate increased by cold acclimation in <i>Drosophila albomicans</i> from natural populations

“…This implies that the distribution expansion of D. albomicans is likely attributed to the intraspecific variation including such strains that have a high cold tolerance and a strong acclimation response. It is noteworthy that D. pallidifrons, which is the most ancestral species in the D. nasuta subgroup (Wakahama et al, 1983;Suzuki et al, 1990), showed a relatively high cold tolerance after the cold acclimation (Fig. 4).…”

Molecular phylogeny of the <i>nasuta</i> subgroup of <i>Drosophila </i>based on 12S rRNA, 16S rRNA and CoI mitochondrial genes, RAPD and ISSR polymorphisms

“…From the beginning of the pioneering work of Wilson et al, (1969), phylogeny of the nasuta subgroup has been extensively studied at various levels of organiEdited by Masatoshi Yamamoto * Corresponding author. E-mail: drosrang@sancharnet.in zations namely, morphophenotypes (Nirmala and Krishnamurthy, 1972), hybridization and hybrid sterility (Ramachandra and Ranganath, 1988), karyotypes (Ranganath and Hägele, 1981;Wakahama et al, 1983;Ranganath and Ushakumari, 1987;Rao and Ranganath, 1991), hybrid salivary chromosomes (Lambert, 1978;Rajasekarasetty et al, 1980), heterochromatin and satellite DNA (Ranganath et al, 1982;Ranganath and Ushakumari, 1987), isozymes and allozymes (Kanapi and Wheeler, 1970;Ramesh and Rajasekarasetty, 1980), glue proteins (Ramesh and Kalisch, 1989), courtship patterns (Tanuja et al, 2001), courtship song (Shao et al, 1997), mitochondrial DNA (Chang et al, 1989;Yu et al, 1999), and male accessory gland proteins (Ram and Ramesh, 2001).…”