scholarly journals The genetic architecture of post-zygotic reproductive isolation between Anopheles coluzzii and An. quadriannulatus

2020 ◽  
Author(s):  
Kevin C. Deitz ◽  
Willem Takken ◽  
Michel A. Slotman
Keyword(s):  
Reproductive Isolation ◽  
Anopheles Gambiae ◽  
X Chromosome ◽  
Genetic Background ◽  
Epistatic Interaction ◽  
Hybrid Sterility ◽  
Anopheles Coluzzii ◽  
Hybrid Male ◽  
Backcross Population ◽  
Complex Species

AbstractThe Anopheles gambiae complex is comprised of eight morphologically indistinguishable species and has emerged as a model system for the study of speciation genetics due to the rapid radiation of its member species over the past two million years. Male hybrids between most An. gambiae complex species pairs are sterile, and some genotype combinations in hybrid males cause inviability. We investigated the genetic basis of hybrid male inviability and sterility between An. coluzzii and An. quadriannulatus by measuring segregation distortion and performing a QTL analysis of sterility in a backcross population. Hybrid males were inviable if they inherited the An. coluzzii X chromosome and were homozygous at one or more loci in 18.9 Mb region of chromosome 3. The An. coluzzii X chromosome has a disproportionately large effect on hybrid sterility when introgressed into an An. quadriannulatus genetic background. Additionally, an epistatic interaction between the An. coluzzii X and a 1.12 Mb, pericentric region of the An. quadriannulatus 3L chromosome arm has a statistically significant contribution to the hybrid sterility phenotype. This same epistatic interaction occurs when the An. coluzzii X is introgressed into the genetic background of An. arabiensis, the sister species of An. quadriannulatus, suggesting that this may represent one of the first Dobzhansky–Muller incompatibilities to evolve early in the radiation of the Anopheles gambiae species complex. We describe the additive effects of each sterility QTL, epistatic interactions between them, and genes within QTL with protein functions related to mating behavior, reproduction, spermatogenesis, and microtubule morphogenesis, whose divergence may contribute to post-zygotic reproductive isolation between An. coluzzii and An. quadriannulatus.

scholarly journals The Genetics of Reproductive Isolation in the Drosophila simulans Clade: X vs. Autosomal Effects and Male vs. Female Effects

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1243-1255 ◽  
Author(s):  
Hope Hollocher ◽  
Chug-I Wu
Keyword(s):  
Reproductive Isolation ◽  
Male Sterility ◽  
X Chromosome ◽  
Hybrid Sterility ◽  
Drosophila Simulans ◽  
Female Sterility ◽  
Hybrid Male ◽  
Hybrid Female ◽  
Hybrid Male Sterility ◽  
Hybrid Inviability

Abstract A strong effect of homozygous autosomal regions on reproductive isolation was found for crosses between the species in the Drosophila simulans clade. Second chromosome regions were introgressed from D. mauritiana and D. sechellia into D. simulans and tested for their homozygous effects on hybrid male and hybrid female sterility and inviability. Most introgressions are fertile as heterozygotes, yet produce sterile male offspring when made homozygous. The density of homozygous autosomal factors contributing to hybrid male sterility is comparable to the density of X chromosome factors for this level of resolution. Female sterility was also revealed, yet the disparity between male and female levels of sterility was great, with male sterility being up to 23 times greater than female sterility. Complete hybrid inviability was also associated with some regions of the second chromosome, yet there were no strong sex differences. In conclusion, we find no evidence to support a strong X chromosome bias in the evolution of hybrid sterility or inviability but do find a very strong sex bias in the evolution of hybrid sterility. In light of these findings, we reevaluate the current models proposed to explain the genetic pattern of reproductive isolation.

PRELIMINARY ANALYSIS OF GENETICS OF HYBRID STERILITY IN CROSSES OF GLOSSINA PALPALIS PALPALIS (ROBINEAU-DESVOIDY) AND GLOSSINA PALPALIS GAMBIENSIS VANDERPLANK

1988 ◽  
Vol 120 (11) ◽  
pp. 997-1001 ◽  
Author(s):  
R.H. Gooding
Keyword(s):  
X Chromosome ◽  
Hybrid Sterility ◽  
Marker Gene ◽  
Glossina Palpalis Palpalis ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Chromosome Marker ◽  
Glossina Palpalis Gambiensis ◽  
Almost All ◽  
Glossina Palpalis

AbstractGlossina palpalis palpalis (Robineau-Desvoidy) and Glossina palpalis gambiensis Vanderplank hybridized readily in the laboratory but hybridized females produced fewer offspring than did females that mated with their own kind. Most hybrid females were fertile when backcrossed to either G. p. palpalis or G. p. gambiensis but almost all hybrid males were sterile. About half of the backcross males were able to fertilize G. p. palpalis and G. p. gambiensis. By using an X chromosome marker gene, tan, evidence was obtained that the X chromosome is involved in hybrid male sterility, either through interaction with the Y chromosome or the autosomes of the other subspecies. There was no evidence for maternally inherited sterility factors of a type that confer unidirectional sterility on hybrid or backcross males.

scholarly journals The genetics of postzygotic isolation in the Drosophila virilis group.

Genetics ◽  
1989 ◽  
Vol 121 (3) ◽  
pp. 527-537 ◽  
Author(s):  
H A Orr ◽  
J A Coyne
Keyword(s):  
Reproductive Isolation ◽  
X Chromosome ◽  
Related Species ◽  
Hybrid Sterility ◽  
Drosophila Virilis ◽  
Female Sterility ◽  
Postzygotic Isolation ◽  
Male And Female ◽  
Virilis Group ◽  
Drosophila Virilis Group

Abstract In a genetic study of postzygotic reproductive isolation among species of the Drosophila virilis group, we find that the X chromosome has the largest effect on male and female hybrid sterility and inviability. The X alone has a discernible effect on postzygotic isolation between closely related species. Hybridizations involving more distantly related species also show large X-effects, although the autosomes may also play a role. In the only hybridization yet subjected to such analysis, we show that hybrid male and female sterility result from the action of different X-linked loci. Our results accord with genetic studies of other taxa, and support the view that both Haldane's rule (heterogametic F1 sterility or inviability) and the large effect of the X chromosome on reproductive isolation result from the accumulation by natural selection of partially recessive or underdominant mutations. We also describe a method that allows genetic analysis of reproductive isolation between species that produce completely sterile or inviable hybrids. Such species pairs, which represent the final stage of speciation, cannot be analyzed by traditional methods. The X chromosome also plays an important role in postzygotic isolation between these species.

scholarly journals Further characterization of the Odysseus locus of hybrid sterility in Drosophila: one gene is not enough.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 201-206 ◽  
Author(s):  
D E Perez ◽  
C I Wu
Keyword(s):  
Related Species ◽  
Genetic Background ◽  
Hybrid Sterility ◽  
Weak Effect ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Closely Related Species ◽  
Drosophila Mauritiana ◽  
Average Gene

Abstract Previously we mapped by genetical and molecular means a gene that contributes to hybrid-male sterility between Drosophila mauritiana and D. simulans to the cytological interval of 16D. In this report, we refine the mapping of this gene, Odysseus (Ods) and show that it can be delineated to a region the size of an average gene. We further demonstrate that, while Ods appears to be a discrete element, it requires other nearby gene(s) to be cointrogressed to confer full hybrid sterility effect. This observation is in agreement with the view that reproductive isolation between closely related species of Drosophila is usually caused by several genes of weak effect from the same species that interact strongly among themselves as well as with the foreign genetic background.

scholarly journals Reticulate speciation and adaptive introgression in the Anopheles gambiae species complex

2014 ◽  
Author(s):  
Jacob Crawford ◽  
Michelle M. Riehle ◽  
Wamdaogo M. Guelbeogo ◽  
Awa Gneme ◽  
N'fale Sagnon ◽  
...  
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Anopheles Gambiae ◽  
X Chromosome ◽  
Species Complex ◽  
Sub Saharan Africa ◽  
Contemporary Gene Flow ◽  
Speciation Continuum ◽  
Primary Vector ◽  
Sub Saharan

Anopheles gambiae, the primary vector of human malaria in sub-Saharan Africa, exists as a series of ecologically specialized subgroups that are phylogenetically nested within the Anopheles gambiae species complex. These species and subgroups exhibit varying degrees of reproductive isolation, sometimes recognized as distinct subspecies. We have sequenced 32 complete genomes from field-captured individuals of Anopheles gambiae, Anopheles gambiae M form (recently named A. coluzzii), sister species A. arabiensis, and the recently discovered ?GOUNDRY? subgroup of A. gambiae that is highly susceptible to Plasmodium. Amidst a backdrop of strong reproductive isolation and adaptive differentiation, we find evidence for introgression of autosomal chromosomal regions among species and subgroups, some of which have facilitated adaptation. The X chromosome, however, is strongly differentiated among all species and subgroups, pointing to a disproportionately large effect of X chromosome genes in driving speciation among anophelines. Strikingly, we find that autosomal introgression has occurred from contemporary hybridization among A. gambiae and A. arabiensis despite strong divergence (~5? higher than autosomal divergence) and isolation on the X chromosome. We find a large region of the X chromosome that has swept to fixation in the GOUNDRY subgroup within the last 100 years, which may be an inversion that serves as a partial barrier to contemporary gene flow. We show that speciation with gene flow results in genomic mosaicism of divergence and introgression. Such a reticulate gene pool connecting vector species and subgroups across the speciation continuum has important implications for malaria control efforts.

SEX CHROMOSOME TRANSLOCATIONS IN THE EVOLUTION OF REPRODUCTIVE ISOLATION

Genetics ◽  
1972 ◽  
Vol 72 (2) ◽  
pp. 317-333
Author(s):  
Martin L Tracey
Keyword(s):  
Reproductive Isolation ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Hybrid Sterility ◽  
Fixation Probability ◽  
Chromosomal Imbalance ◽  
Haldane’S Rule ◽  
Chromosome Translocations ◽  
Haldane's Rule ◽  
Heterogametic Sex

ABSTRACT Haldane's rule states that in organisms with differentiated sex chromosomes, hybrid sterility or inviability is generally expressed more frequently in the heterogametic sex. This observation has been variously explained as due to either genic or chromosomal imbalance. The fixation probabilities and mean times to fixation of sex-chromosome translocations of the type necessary to explain Haldane's rule on the basis of chromosomal imbalance have been estimated in small populations of Drosophila melanogaster. The fixation probability of an X chromosome carrying the long arm of the Y(X.YL) is approximately 30% greater than expected under the assumption of no selection. No fitness differences associated with the attached YL segment were detected. The fixation probability of a deficient Y chromosome is 300% greater than expected when the X chromosome contains the deleted portion of the Y. It is suggested that sex-chromosome translocations may play a role in the establishment of reproductive isolation.

Genetic analysis of hybrid sterility in crosses of the tsetse flies Glossina palpalis palpalis and Glossina palpalis gambiensis (Diptera: Glossinidae)

1997 ◽  
Vol 75 (7) ◽  
pp. 1109-1117 ◽  
Author(s):  
R. H. Gooding
Keyword(s):  
Linkage Group ◽  
Male Sterility ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Hybrid Sterility ◽  
Glossina Palpalis Palpalis ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Reciprocal Crosses ◽  
Glossina Palpalis

Reciprocal crosses of Glossina palpalis gambiensis Vanderplank and Glossina palpalis palpalis (Robineau-Desvoidy) were carried out using flies that had four marker genes on the X chromosome, two in linkage group II and one in linkage group III: The results of the reciprocal crosses conformed to Haldane's rule: F1 males were sterile and most F1 females were fertile. F1 females mated to G. p. gambiensis were more likely to be fertilized than females that were mated to G. p. palpalis. In three of the four experiments, the fertility of backcross females was not significantly different from that of F1 females, and there was little evidence that specific chromosomal combinations influenced the fertility of backcross females. Intrachromosomal recombination was lower in hybrid females than in G. p. palpalis. The major genetic factor associated with sterility among backcross males was the presence of sex chromosomes from two subspecies; a minor factor was the number of heterozygous autosomes, but interactions between sex chromosomes and autosomes from different taxa did not contribute to hybrid male sterility. Evidence is presented that a major factor causing hybrid male sterility lies between the loci tan (an eye color) and Est-t (testicular esterase) on the X chromosome. The use of differences between the fertility of males produced by backcrossing F1 females to the two parental subspecies as indicators that other X chromosome loci have a role in hybrid sterility is discussed.

scholarly journals Genetics of hybrid male sterility between drosophila sibling species: a complex web of epistasis is revealed in interspecific studies.

Genetics ◽  
1994 ◽  
Vol 138 (2) ◽  
pp. 329-341 ◽  
Author(s):  
M F Palopoli ◽  
C I Wu
Keyword(s):  
Male Sterility ◽  
X Chromosome ◽  
Functional Divergence ◽  
Hybrid Sterility ◽  
Sequence Divergence ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Common Component ◽  
Drosophila Mauritiana ◽  
Linkage Relationships

Abstract To study the genetic differences responsible for the sterility of their male hybrids, we introgressed small segments of an X chromosome from Drosophila simulans into a pure Drosophila mauritiana genetic background, then assessed the fertility of males carrying heterospecific introgressions of varying size. Although this analysis examined less than 20% of the X chromosome (roughly 5% of the euchromatic portion of the D. simulans genome), and the segments were introgressed in only one direction, a minimum of four factors that contribute to hybrid male sterility were revealed. At least two of the factors exhibited strong epistasis: males carrying either factor alone were consistently fertile, whereas males carrying both factors together were always sterile. Distinct spermatogenic phenotypes were observed for sterile introgressions of different lengths, and it appeared that an interaction between introgressed segments also influenced the stage of spermatogenic defect. Males with one category of introgression often produced large quantities of motile sperm and were observed copulating, but never inseminated females. Evidently these two species have diverged at a large number of loci which have varied effects on hybrid male fertility. By extrapolation, we estimate that there are at least 40 such loci on the X chromosome alone. Because these species exhibit little DNA-sequence divergence at arbitrarily chosen loci, it seems unlikely that the extensive functional divergence observed could be due mainly to random genetic drift. Significant epistasis between conspecific genes appears to be a common component of hybrid sterility between recently diverged species of Drosophila. The linkage relationships of interacting factors could shed light on the role played by epistatic selection in the dynamics of the allele substitutions responsible for reproductive barriers between species.

Genetic basis of sterility in hybrids from crosses of Glossina morsitans submorsitans and Glossina morsitans morsitans (Diptera: Glossinidae)

Genome ◽  
1989 ◽  
Vol 32 (3) ◽  
pp. 479-485 ◽  
Author(s):  
R. H. Gooding
Keyword(s):  
Linkage Group ◽  
X Chromosome ◽  
Hybrid Sterility ◽  
Glossina Morsitans Morsitans ◽  
Marker Genes ◽  
Glossina Morsitans ◽  
Hybrid Male ◽  
X Chromosomes ◽  
Glossina Morsitans Submorsitans ◽  
Group Ii

Glossina morsitans submorsitans Newstead and Glossina morsitans morsitans Westwood carrying two marker genes on the X chromosome, two in linkage group II, and one in linkage group III were hybridized. About 17% of the F1 and from 33 to 56% of the backcross males fertilized G. m. submorsitans, but only one F1 and two backcross males fertilized G. m. morsitans. Similarly, F1 and backcross females were fertilized by G. m. submorsitans but rarely by G. m. morsitans. Chromosomal composition of F1 and backcross males indicated that hybrid male sterility is due to incompatibility of the X chromosome from one subspecies and the Y from the other subspecies or possibly an incompatibility between X chromosomes and autosomes from different subspecies. Results are discussed in the context of a model for evolution of X and Y incompatibility and a model for evolution of maternally inherited factors that cause unidirectional sterility in males. In hybrid females, intrachromosomal recombination was suppressed in the X chromosome and in linkage group II. Fertility of backcross females, mated to G. m. submorsitans, could not be related to the chromosomal composition of the females.Key words: Glossina, hybrid sterility, tsetse, X chromosomes.

scholarly journals The Broom of the Sorcerer's Apprentice: The Fine Structure of a Chromosomal Region Causing Reproductive Isolation Between Two Sibling Species of Drosophila

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1287-1298 ◽  
Author(s):  
Andrew W Davis ◽  
Chug-I Wu
Keyword(s):  
Reproductive Isolation ◽  
Sibling Species ◽  
Related Species ◽  
Hybrid Sterility ◽  
Drosophila Genome ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Closely Related Species ◽  
Drosophila Mauritiana ◽  
Two Factors

Abstract How many genes contribute to reproductive isolation between closely related species? We determined the number of genes located in the 9D-12B region of the Drosophila mauritiana X chromosome that cause hybrid male sterility in a D. simulans background. Previous low resolution studies suggested that a single hybrid sterility factor was associated with this region. In this study, by taking advantage of a cluster of visible and DNA markers, we identified three D. mauritiana factors in this region and then subjected one of them to detailed analysis. This factor again turned out to be comprised of three factors; one of which, mapped to within 200 kb, may in fact be two factors. The title refers to this exercise of splitting sterile introgressions into ever smaller ones, each of which retains partial or full sterility effects. In a region representing a mere 3% of the Drosophila genome, no fewer than six loci of hybrid sterility were identified between two sibling species that have not shown clear divergence at the molecular level. These results suggest that levels of genetic divergence between closely related species may be quite high for functionally important traits even when the opposite is true for randomly chosen loci.

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