Metaphase karyotype differentiation in eight species of the montium subgroup of Drosophila

Shyamala, B. V.; Ranganath, H. A.

doi:10.1007/bf00121512

Cited by 6 publications

(5 citation statements)

References 21 publications

(20 reference statements)

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“…The event clearly affected the whole Y chromosome, since in many species all genes that are Y-linked in the montium ancestor became present in females ( Fig 3 ). Many montium species have been investigated cytogenetically; all are XY/XX and have an X chromosome with a single arm [ 35 , 36 ]. These observations make the montium case very interesting, because the absence of a two-armed X implies that the current Y chromosome cannot be a neoY chromosome, as has been suggested for D .…”

Section: Resultsmentioning

confidence: 99%

An investigation of Y chromosome incorporations in 400 species of Drosophila and related genera

et al. 2018

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Y chromosomes are widely believed to evolve from a normal autosome through a process of massive gene loss (with preservation of some male genes), shaped by sex-antagonistic selection and complemented by occasional gains of male-related genes. The net result of these processes is a male-specialized chromosome. This might be expected to be an irreversible process, but it was found in 2005 that the Drosophila pseudoobscura Y chromosome was incorporated into an autosome. Y chromosome incorporations have important consequences: a formerly male-restricted chromosome reverts to autosomal inheritance, and the species may shift from an XY/XX to X0/XX sex-chromosome system. In order to assess the frequency and causes of this phenomenon we searched for Y chromosome incorporations in 400 species from Drosophila and related genera. We found one additional large scale event of Y chromosome incorporation, affecting the whole montium subgroup (40 species in our sample); overall 13% of the sampled species (52/400) have Y incorporations. While previous data indicated that after the Y incorporation the ancestral Y disappeared as a free chromosome, the much larger data set analyzed here indicates that a copy of the Y survived as a free chromosome both in montium and pseudoobscura species, and that the current Y of the pseudoobscura lineage results from a fusion between this free Y and the neoY. The 400 species sample also showed that the previously suggested causal connection between X-autosome fusions and Y incorporations is, at best, weak: the new case of Y incorporation (montium) does not have X-autosome fusion, whereas nine independent cases of X-autosome fusions were not followed by Y incorporations. Y incorporation is an underappreciated mechanism affecting Y chromosome evolution; our results show that at least in Drosophila it plays a relevant role and highlight the need of similar studies in other groups.

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Section: Resultsmentioning

confidence: 99%

An investigation of Y chromosome incorporations in 400 species of Drosophila and related genera

et al. 2018

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“…Analysis of the metaphase karyotypes of the species under investigation by Shyamala and Ranganath (1989) has revealed that the composition of the karyotype of each species is distinctly different from the other. This remarkable degree of differentiation is mainly due to the extensive variability of the fourth and the Y chromosomes.…”

Section: Resultsmentioning

confidence: 99%

“…In-depth studies pertaining to evolutionary relationships among the Indian members of the montium subgroup have not received the attention of the investigators. We have reported the nature and pattern of karyotypic divergence among a few members of the montium subgroup available from this part of the country (Shyamala & Ranganath, 1989). In continuation of this, by way of analyzing a few allozymes, we herein report and discuss the extent of genetic divergence among a few members of the montium subgroup of Drosophila, and present a biochemical dendrogram for these species.…”

Section: Introductionmentioning

confidence: 99%

Biochemical phylogeny of seven Indian species of the montium subgroup of Drosophila

Shyamala

Ranganath

1990

Genetica

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Seven species of the montium subgroup of Drosophila found in South India were analysed with polyacrylamide disc electrophoresis. Eleven loci coding for enzymes were surveyed. The genetic distances between species have been measured. The dendrogram revealed three clusters. The first cluster includes D. nagarholensis, D. agumbensis, D. jambulina and D. kikkawai; the second group consists of D. truncata and D. anomelani; while D. mysorensis was the only species of the third group.

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“…Altogether nine types of IV chromosome and four types of Y chromosome have been recorded in the natural populations of the species (BAIMAI et al 1986). Some earlier studies carried out in several Indian populations have detected two types of IV chromosome, two types of X-chromosome and the B-chromosomes in this species (SHYAMALA and RANGANATH 1989;GuPTA and SuNDARAN 1995). The two types of IV chromosome comprised the large acrocentric and the medium metacentric.…”

Section: Resultsmentioning

confidence: 66%

Ecogeographic differentiation of metaphase karyotypes in natural populations ofDrosophila kikkawai

Sundaran

Gupta

1997

Caryologia

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Metaphase karyotype differentiation in eight species of the montium subgroup of Drosophila

Cited by 6 publications

References 21 publications

An investigation of Y chromosome incorporations in 400 species of Drosophila and related genera

An investigation of Y chromosome incorporations in 400 species of Drosophila and related genera

Biochemical phylogeny of seven Indian species of the montium subgroup of Drosophila

Ecogeographic differentiation of metaphase karyotypes in natural populations ofDrosophila kikkawai

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