Photographic polytene chromosome maps for Glossina morsitans submorsitans (Diptera: Glossinidae): cytogenetic analysis of a colony with sex-ratio distortion

Photographic polytene chromosome maps from trichogen cells of pharate adult Glossina morsitans submorsitans were constructed. Using the standard system employed to map polytene chromosomes of Drosophila, the characteristic landmarks were described for the X chromosome and the two autosomes (L1 and L2). Sex-ratio distortion, which is expressed in male G. m. submorsitans, was found to be associated with an X chromosome (XB) that contains three inversions in each arm. Preliminary data indicate no differences in the fecundity of XAXA and XAXB females, but there are indications that G. m. submorsitans in colonies originating from Burkina Faso and Nigeria have genes on the autosomes and (or) the Y chromosome that suppress expression of sex-ratio distortion.Key words: tsetse, Glossina morsitans submorsitans, polytene chromosome maps, inversions, sex-ratio distortion.

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MAPPING FOUR LOCI IN GLOSSINA MORSITANS SUBMORSITANS NEWSTEAD (DIPTERA: GLOSSINIDAE)

The Canadian Entomologist ◽

10.4039/ent121823-9 ◽

1989 ◽

Vol 121 (9) ◽

pp. 823-824 ◽

Cited By ~ 3

Author(s):

R.H. Gooding ◽

B.M. Rolseth ◽

S.A.Tarimo Nesbitt

Keyword(s):

Sex Ratio ◽

X Chromosome ◽

Sex Chromosomes ◽

B Chromosomes ◽

Linkage Groups ◽

Glossina Morsitans ◽

Polymorphic Loci ◽

Glossina Morsitans Submorsitans ◽

Ratio Distortion ◽

Sex Ratio Distortion

Glossina morsitans submorsitans Newstead has two pairs of autosomes, a pair of sex chromosomes (males are heterogametic), and from two to seven supernumerary (=B) chromosomes (Southern and Pel1 1973). The only information allowing assignment of loci to linkage groups in this subspecies is that electrophoretic evidence suggests that five polymorphic loci, including Est-2 and Mdh, are autosomal (Gooding 1984a), and breeding experiments indicate that sex ratio distortion, favoring production of females, is due to an X chromosome-linked factor (Gooding 1986).

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Sex ratio distortion in Glossina morsitans submorsitans Newstead (Diptera: Glossinidae)

Bulletin of Entomological Research ◽

10.1017/s0007485300011421 ◽

1984 ◽

Vol 74 (2) ◽

pp. 311-315 ◽

Cited By ~ 10

Author(s):

P. Rawlings ◽

I. Maudlin

Keyword(s):

Sex Ratio ◽

Female Offspring ◽

Glossina Morsitans ◽

Selective Abortion ◽

Glossina Morsitans Submorsitans ◽

Laboratory Colony ◽

Control Programmes ◽

Genetic Aberration ◽

Ratio Distortion ◽

Sex Ratio Distortion

AbstractA laboratory colony of Glossina morsitans submorsitans Newst. originating from Nigeria exhibits an excess of females over males. The sex ratio distortion of more than two females to one male was studied by the maintenance of individual flies. Five males sired more than ten daughters without producing any sons when mated to several females, whilst other males fathered approximately equal numbers of male and female offspring; there was no evidence for selective abortion of male embryos. The presence of these ‘distorter’ males, which produce only female offspring, was found to cause the sex ratio distortion. The results are discussed with reference to data from the field which indicate that this genetic aberration is not confined to the laboratory; possible implications for chemical control programmes are assessed.

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Salivary polytene chromosome mapping of Anopheles (Cellia) subpictus Grassi (Culicidae: Diptera)

Genome ◽

10.1139/g04-120 ◽

2005 ◽

Vol 48 (2) ◽

pp. 241-246 ◽

Cited By ~ 6

Author(s):

S Chaudhry ◽

Neetu ◽

S Gupta ◽

J S Chhilar

Keyword(s):

Polytene Chromosome ◽

X Chromosome ◽

Dna Sequences ◽

Molecular Taxonomy ◽

Polytene Chromosomes ◽

Chromosome Mapping ◽

Anopheles Subpictus ◽

Chromosome Inversion ◽

Chromosome Maps ◽

The Comparative Study

With the introduction of molecular taxonomy of mosquitoes, polytene chromosome maps have become indispensable as standard references for locating genes, puffs, and inversion breakpoints of unique DNA sequences. We present a line map and a photomap of the salivary polytene chromosomes of Anopheles (Cellia) subpictus Grassi, an important emerging vector of malaria in India. In addition, we discuss the nature of this species complex consisting of sibling species A, B, C, and D. The comparative study is in relevance to the X chromosome heterozygous inversion differences between 2 allopatric populations of the species and the recognition of 4 X-chromosome inversion genotypes viz: species A–X+a+b, B–Xab, C–Xa+b and D–X+ab.Key words: Anopheles subpictus, polytene chromosome map.

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Sex ratio distortion and semi-sterility in the progeny of irradiated Glossina morsitans

Genetics Research ◽

10.1017/s0016672300013331 ◽

1973 ◽

Vol 21 (2) ◽

pp. 153-165 ◽

Cited By ~ 10

Author(s):

C. F. Curtis ◽

P. A. Langley ◽

A. R. Mews ◽

E. D. Offori ◽

D. I. Southern ◽

...

Keyword(s):

Sex Ratio ◽

Gamma Radiation ◽

Population Control ◽

Sterile Male ◽

Glossina Morsitans ◽

Control Target ◽

Ratio Distortion ◽

The Mean ◽

Almost All ◽

Sex Ratio Distortion

SUMMARYMale Glossina morsitans were subjected to various doses of gamma radiation in air or nitrogen and mated to untreated females. The sex ratio of the F1 progeny was biased towards males, and this may be explained by the extra vulnerability to dominant lethal induction that the presence of the large X chromosome gives to female determining sperms. The mean fertility of the F1 progeny was subnormal. This was due to the induction of 50 % sterility in a large proportion of F1 individuals. Cytogenetic examination of the progeny of outcrosses of F1 individuals indicated that in most of the semi-steriles there were translocations involving the large autosomes or the Y chromosomes. Almost all the normally fertile F1 flies gave only cytogenetically normal progeny. The F1 sex-ratio distortion and semi-sterility would provide a ‘bonus’ in the application of the sterile male technique, which would amount to a 15–50% saving in the releases required to achieve a population control target compared with the requirement if the F1 was normal.

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Sex Ratios in a Warming World: Thermal Effects on Sex-Biased Survival, Sex Determination, and Sex Reversal

Journal of Heredity ◽

10.1093/jhered/esab006 ◽

2021 ◽

Vol 112 (2) ◽

pp. 155-164

Author(s):

Suzanne Edmands

Keyword(s):

High Temperature ◽

Sex Ratio ◽

Sex Determination ◽

Heat Tolerance ◽

Sex Ratios ◽

Sex Reversal ◽

Survival Sex ◽

Ratio Distortion ◽

Warming World ◽

Sex Ratio Distortion

Abstract Rising global temperatures threaten to disrupt population sex ratios, which can in turn cause mate shortages, reduce population growth and adaptive potential, and increase extinction risk, particularly when ratios are male biased. Sex ratio distortion can then have cascading effects across other species and even ecosystems. Our understanding of the problem is limited by how often studies measure temperature effects in both sexes. To address this, the current review surveyed 194 published studies of heat tolerance, finding that the majority did not even mention the sex of the individuals used, with <10% reporting results for males and females separately. Although the data are incomplete, this review assessed phylogenetic patterns of thermally induced sex ratio bias for 3 different mechanisms: sex-biased heat tolerance, temperature-dependent sex determination (TSD), and temperature-induced sex reversal. For sex-biased heat tolerance, documented examples span a large taxonomic range including arthropods, chordates, protists, and plants. Here, superior heat tolerance is more common in females than males, but the direction of tolerance appears to be phylogenetically fluid, perhaps due to the large number of contributing factors. For TSD, well-documented examples are limited to reptiles, where high temperature usually favors females, and fishes, where high temperature consistently favors males. For temperature-induced sex reversal, unambiguous cases are again limited to vertebrates, and high temperature usually favors males in fishes and amphibians, with mixed effects in reptiles. There is urgent need for further work on the full taxonomic extent of temperature-induced sex ratio distortion, including joint effects of the multiple contributing mechanisms.

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Sex Chromosome Meiotic Drive in Stalk-Eyed Flies

Genetics ◽

10.1093/genetics/147.3.1169 ◽

1997 ◽

Vol 147 (3) ◽

pp. 1169-1180 ◽

Cited By ~ 6

Author(s):

Daven C Presgraves ◽

Emily Severance ◽

Gerald S Willrinson

Keyword(s):

Sex Ratio ◽

Sex Chromosome ◽

Sex Ratios ◽

Natural Populations ◽

Meiotic Drive ◽

Operational Sex Ratio ◽

Genetic Modifiers ◽

Ratio Distortion ◽

The Impact ◽

Sex Ratio Distortion

Meiotically driven sex chromosomes can quickly spread to fixation and cause population extinction unless balanced by selection or suppressed by genetic modifiers. We report results of genetic analyses that demonstrate that extreme female-biased sex ratios in two sister species of stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei, are due to a meiotic drive element on the X chromosome (Xd). Relatively high frequencies of Xd in C. dalmanni and C. whitei (13–17% and 29%, respectively) cause female-biased sex ratios in natural populations of both species. Sex ratio distortion is associated with spermatid degeneration in male carriers of Xd. Variation in sex ratios is caused by Y-linked and autosomal factors that decrease the intensity of meiotic drive. Y-linked polymorphism for resistance to drive exists in C. dalmanni in which a resistant Y chromosome reduces the intensity and reverses the direction of meiotic drive. When paired with Xd, modifying Y chromosomes (Ym) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny. The absence of sex ratio distortion in closely related monomorphic outgroup species suggests that this meiotic drive system may predate the origin of C. whitei and C. dalmanni. We discuss factors likely to be involved in the persistence of these sex-linked polymorphisms and consider the impact of Xd on the operational sex ratio and the intensity of sexual selection in these extremely sexually dimorphic flies.

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