The actin loci in the genus Drosophila : establishment of chromosomal homologies among five palearctic species of the Drosophila obscura group by in situ hybridization

Abstract

Chromosomal homologies among the four palearctic Drosophila obscura group species D. ambigua, D. tristis, D. obscura, and D. subsilvestris and the "trans-palearctic" species D. bifasciata were established by in situ hybridization using the 5C actin gene of D. melanogaster as a probe. In all species two labeling sites were detected in each of chromosomal elements C and E and one in each of chromosomal elements A and D. In addition one labeling site was detected on element B for the species D. subsilvestris and D. bifasciata. The conservative distribution pattern of the genes of the actin multigene family, the similarities of the locations of the actin genes in the chromosomes of the five species studied, together with the concordant evidence of synteny of visible and other genetic markers as well as the similarities in banding patterns, all agree with the conclusion that the chromosomal elements have retained their essential identity throughout the evolution of these species. Using in situ hybridization detailed information of some homologous regions of chromosomes can also be established.

The actin loci in the genus Drosophila: establishment of chromosomal homologies among five nearctic species of the Drosophila obscura group by in situ hybridization

“…In the genomes of D. melanogaster (Fyrberg et al 1980;Tobin et al 1980), D. virilis, D. robusta, D. hydei and D. grimshawi (Loukas and Kafatos 1986), D. subobscura and D. madeirensis (Loukas and Kafatos 1988), D. ambigua, D. tristis and D. obscura (Bondinas et al 2001), six actin loci could be observed similarly dispersed over the chromosomal elements A (one locus), C (two loci), D (one locus) and E (two loci). Recently, an additional actin locus on element B was found for D. subsilvestris and D. bifasciata by Bondinas et al (2001).…”

“…Recently, an additional actin locus on element B was found for D. subsilvestris and D. bifasciata by Bondinas et al (2001). In D. pseudoobscura and D. persimilis of the pseudoobscura subgroup, the 5C actin probe labeled the six actin sites so far observed in the entire genus Drosophila, but in addition one site in element A and one in element B.…”

“…In all the species studied six different actin loci were found, similarly dispersed on the chromosomal elements A (one locus), C (two loci), D (one locus) and E (two loci). Recently, Bondinas et al (2001) observed in a study of five palearctic D. obscura species the same pattern of dispersion of the six actin genes in the chromosomes of D. ambigua, D. tristis and D. obscura. Surprisingly, in the chromosomes of the species D. subsilvestris and D. bifasciata seven labeling sites were detected, the six previous ones and an additional site on element B.…”

“…This problem can be avoided by the technique of in situ hybridization, a powerful method that is potentially able to supplement the classical approaches and overcome their limitations (Steinemann 1982;Steinemann et al 1984;Kafatos 1986, 1988;Schneuwly et al 1986;Whiting et al 1989;Steinemann and Steinemann 1990;Terol et al 1991;Visa et al 1991;Molto et al 1992;Segarra and Aguade 1992;Segarra et al 1995Segarra et al , 1996Ranz et al 1997;Cuenca et al 1998;Bondinas et al 2001).…”

The polytene dot chromosome of Drosophila: D. melanogaster and D. subobscura

“…Muller (1940) proposed that the chromosome arms are conserved as homologous elements across the genus Drosophila. This hypothesis has been amply confirmed by, for example, in situ hybridization to polytene chromosomes (see Bondinas et al 2001 and references therein). Cuenca et al (1998) have shown that the F elements of D. melanogaster and D. subobscura are homologous.…”