Inter-population sex chromosome polymorphism in the grasshopper Podisma pedestris

Chromosoma ◽  
1970 ◽  
Vol 31 (3) ◽  
pp. 291-308 ◽  
Author(s):  
B. John ◽  
G. M. Hewitt
Keyword(s):  
Sex Chromosome ◽  
Chromosome Polymorphism

On the Maintenance of Sex Chromosome Polymorphism by Sex-Antagonistic Selection

2011 ◽  
Vol 178 (4) ◽  
pp. 515-524 ◽  
Author(s):  
Olivier Blaser ◽  
Samuel Neuenschwander ◽  
Nicolas Perrin
Keyword(s):  
Sex Chromosome ◽  
Chromosome Polymorphism ◽  
Antagonistic Selection ◽  
Maintenance Of Sex

scholarly journals The evolution of the Y chromosome with X-Y recombination.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 711-720
Author(s):  
A G Clark
Keyword(s):  
Natural Selection ◽  
Y Chromosome ◽  
Meiotic Recombination ◽  
Population Genetic ◽  
Sex Chromosome ◽  
Genetic Model ◽  
Chromosome Polymorphism ◽  
Significant Finding ◽  
Special Cases ◽  
Theoretical Population

Abstract A theoretical population genetic model is developed to explore the consequences of X-Y recombination in the evolution of sex chromosome polymorphism. The model incorporates one sex-determining locus and one locus subject to natural selection. Both loci have two alleles, and the rate of classical meiotic recombination between the loci is r. The alleles at the sex-determining locus specify whether the chromosome is X or Y, and the alleles at the selected locus are arbitrarily labeled A and a. Natural selection is modeled as a process of differential viabilities. The system can be expressed in terms of three recurrence equations, one for the frequency of A on the X-bearing gametes produced by females, one for each of the frequency of A on the X- and Y-bearing gametes produced by males. Several special cases are examined, including X chromosome dominance and symmetric selection. Unusual equilibria are found with the two sexes having very different allele frequencies at the selected locus. A significant finding is that the allowance of recombination results in a much greater opportunity for polymorphism of the Y chromosome. Tighter linkage results in a greater likelihood for equilibria with a large difference between the sex chromosomes in allele frequency.

Speciation in black flies

Genome ◽  
1989 ◽  
Vol 32 (4) ◽  
pp. 500-509 ◽  
Author(s):  
Klaus Rothfels
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Sympatric Speciation ◽  
Chromosome Polymorphism ◽  
Black Flies ◽  
Closely Related Species ◽  
Black Fly ◽  
Progressive Development ◽  
Temporal Relationships ◽  
Species Pairs

In many Simuliidae, patterns of spatial and temporal relationships among the most closely related species are more readily interpreted in terms of sympatric speciation than of allopatric speciation. Specific examples are (i) the allotriploid taxa in Gymnopais and other genera, (ii) the black fly faunas of geologically recent islands (Tahiti), and (iii) species in Prosimulium onychodactylum, a prototype of a continental multisibling species complex. A model of sympatric speciation is presented based on coadaptation of polymorphic sex chromosomes in pairs reinforced by progressive development of assortative mating. This model predicts that (i) populations should frequently exhibit sex-chromosome polymorphism, (ii) these sex-chromosome polymorphisms, and autosomal ones, should in some cases display linkage or association disequilibria, (iii) species pairs or complexes should be incurred that differ only in sex chromosomes and that share extensive ancestral autosomal polymorphisms, and (iv) such species should differ in their biology and perhaps their present-day distribution. Recent publications and observations are in accordance, in general, with predictions from the model. Genetic control, e.g., of diapause, larval developmental timing, and niche preference or ethology, could substitute as a basis of incipient cleavage. The evidence for sympatric speciation is purely inferential, but this is equally true for the allopatric interpretation, and in black flies the circumstantial evidence for prevalence of sympatric speciation appears more compelling. This is not to deny the efficacy of allopatry and founder effect in the origin of some species complexes.Key words: sympatric speciation, black fly, evolution.

Sex Chromosome Polymorphism in Domestic Cattle

1968 ◽  
Vol 59 (1) ◽  
pp. 35-36 ◽  
Author(s):  
NAT M. KIEFFER ◽  
T. C. CARTWRIGHT
Keyword(s):  
Sex Chromosome ◽  
Chromosome Polymorphism

scholarly journals MAINTENANCE OF THE THREE SEX CHROMOSOME POLYMORPHISM IN THE PLATYFISH, XIPHOPHORUS MACULATUS

Evolution ◽  
1980 ◽  
Vol 34 (4) ◽  
pp. 663-672 ◽  
Author(s):  
Steven Hecht Orzack ◽  
Joel J. Sohn ◽  
Klaus D. Kallman ◽  
Simon A. Levin ◽  
Ross Johnston
Keyword(s):  
Sex Chromosome ◽  
Chromosome Polymorphism ◽  
Xiphophorus Maculatus

Maintenance of the Three Sex Chromosome Polymorphism in the Platyfish, Xiphophorus maculatus

Evolution ◽  
1980 ◽  
Vol 34 (4) ◽  
pp. 663 ◽  
Author(s):  
Steven Hecht Orzack ◽  
Joel J. Sohn ◽  
Klaus D. Kallman ◽  
Simon A. Levin ◽  
Ross Johnston
Keyword(s):  
Sex Chromosome ◽  
Chromosome Polymorphism ◽  
Xiphophorus Maculatus

Sex chromosome polymorphism in Bulgarian populations ofMicrotus guentheri(Danford & Alston, 1880)

2008 ◽  
Vol 42 (5-8) ◽  
pp. 261-267 ◽  
Author(s):  
Tsenka G. Chassovnikarova ◽  
Georgi G. Markov ◽  
Nasko I. Atanasov ◽  
Hristo A. Dimitrov
Keyword(s):  
Sex Chromosome ◽  
Chromosome Polymorphism

Sex chromosome polymorphism in the Simulium tuberosum complex (Lundström) (Diptera: Simuliidae)

1984 ◽  
Vol 62 (4) ◽  
pp. 647-658 ◽  
Author(s):  
G. F. Mason
Keyword(s):  
United States ◽  
Sibling Species ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Distinct Species ◽  
Chromosome Polymorphism ◽  
Northeastern United States ◽  
Primary Zone ◽  
Heteromorphic Sex Chromosomes ◽  
Unusual Chromosome

These studies on the Simulium tuberosum complex have revealed the presence of a number of closely related sibling species which are distinguished by the banding pattern on their sex chromosomes. Collections were made over wide geographic areas of North America and the distributions of the various types found were recorded. Included are areas in northeastern United States with sites at which a number of the sibling species are sympatric. At these sites the separation of one taxa from another is not clear and a number of intra- and inter-sibling sex chromosome polymorphisms were detected. Included in these polymorphs were larvae with unusual chromosome combinations, including females with heteromorphic sex chromosomes. Arguments are made for some of the divisions as distinct species and for sex chromosome polymorphism in others. Based on the evidence of the geographic distribution, it is suggested that the area of sympatry in which polymorphism in all of the division of the complex was found is a primary zone of speciation.

Sign in / Sign up

Export Citation Format

Share Document