scholarly journals Genetics of Male and Female Sterility in Hybrids of Drosophila pseudoobscura and D. persimilis

Genetics ◽  
1987 ◽  
Vol 116 (4) ◽  
pp. 555-563
Author(s):  
H Allen Orr

ABSTRACT The genetic basis of male and female sterility in hybrids of Drosophila pseudoobscura-Drosophila persimilis was studied using backcross analysis. Previous studies indirectly assessed male fertility by measuring testis size; these studies concluded that male sterility results from an X chromosome-autosome imbalance. By directly scoring for the production of motile sperm, male sterility is shown to be largely due to an incompatibility between genes on the X and Y chromosomes of these two species. These species have diverged at a minimum of nine loci affecting hybrid male fertility. Semisterility of hybrid females appears to result from an X chromosome-cytoplasm interaction; the X chromosome thus has the largest effect on sterility in both male and female hybrids. This is apparently the first analysis of the genetic basis of female sterility, or of sterility/inviability affecting both sexes, in an animal hybridization.

Genetics ◽  
2019 ◽  
Vol 212 (3) ◽  
pp. 801-813 ◽  
Author(s):  
Yu Bi ◽  
Xiaoliang Ren ◽  
Runsheng Li ◽  
Qiutao Ding ◽  
Dongying Xie ◽  
...  

Hybrid male progeny from interspecies crosses are more prone to sterility or inviability than hybrid female progeny, and the male sterility and inviability often demonstrate parent-of-origin asymmetry. However, the underlying genetic mechanism of asymmetric sterility or inviability remains elusive. We previously established a genome-wide hybrid incompatibility (HI) landscape between Caenorhabditis briggsae and C. nigoni by phenotyping a large collection of C. nigoni strains each carrying a C. briggsae introgression. In this study, we systematically dissect the genetic mechanism of asymmetric sterility and inviability in both hybrid male and female progeny between the two species. Specifically, we performed reciprocal crosses between C. briggsae and different C. nigoni strains that each carry a GFP-labeled C. briggsae genomic fragment referred to as introgression, and scored the HI phenotypes in the F1 progeny. The aggregated introgressions cover 94.6% of the C. briggsae genome, including 100% of the X chromosome. Surprisingly, we observed that two C. briggsaeX fragments that produce C. nigoni male sterility as an introgression rescued hybrid F1 sterility in males fathered by C. briggsae. Subsequent backcrossing analyses indicated that a specific interaction between the X-linked interaction and one autosome introgression is required to rescue the hybrid male sterility. In addition, we identified another two C. briggsae genomic intervals on chromosomes II and IV that can rescue the inviability, but not the sterility, of hybrid F1 males fathered by C. nigoni, suggesting the involvement of differential epistatic interactions in the asymmetric hybrid male fertility and inviability. Importantly, backcrossing of the rescued sterile males with C. nigoni led to the isolation of a 1.1-Mb genomic interval that specifically interacts with an X-linked introgression, which is essential for hybrid male fertility. We further identified three C. briggsae genomic intervals on chromosome I, II, and III that produced inviability in all F1 progeny, dependent on or independent of the parent-of-origin. Taken together, we identified multiple independent interacting loci that are responsible for asymmetric hybrid male and female sterility, and inviability, which lays a foundation for their molecular characterization.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 822B-822 ◽  
Author(s):  
Alan G. Smith* ◽  
Nicole Gardner ◽  
Elizabeth Zimmermann

Flower longevity is an important character in many ornamental crops. The processes of pollination and fertilization can cause senescence of the petals through the action of ethylene or its precursors. Preventing the production of pollen and therefore pollination could delay the senescence of petals. We tested whether male-sterility would increase flower longevity in petunia. The gene consisted of a stamen-specific promoter isolated from a Lycopersicon esculentum gene driving the expression of a barnase. Barnase is a RNase that is cytotoxic. The gene was introduced into `Lavender Storm' and `Purple Wave' petunia by Agrobacterium- mediated gene transfer. Five independent transgenic lines of both cultivars were regenerated, rooted, and grown in a greenhouse. All lines showed complete male-sterility as measured by the lack of detectable pollen. Two transgenic lines and a non-transformed control of each cultivar were propagated vegetatively and the flower longevity of each genotype was determined in a greenhouse experiment. There were two treatments: no pollination or pollination with cross-compatible pollen. All sterile genotypes that were not pollinated had increased flower longevity relative to pollinated sterile flowers or either treatment of male fertile (non-transformed) genotypes. These results indicate an application for sterility in the production of petunia flowers with increased longevity. Male and female sterility may be applicable in other ornamental crops where pollination or fertilization is a trigger to petal senescence.


2018 ◽  
Author(s):  
Zhongying Zhao ◽  
Yu Bi ◽  
Xiaoliang Ren ◽  
Runsheng Li ◽  
Qiutao Ding ◽  
...  

Hybrid male progeny from interspecies cross are more prone to sterility or inviability than hybrid female progeny, and the male sterility and inviability often demonstrate a parent-of-origin asymmetry. However, the underlying mechanism of asymmetric sterility or inviability remains elusive. We previously established a genome-wide hybrid incompatibility (HI) landscape between Caenorhabditis briggsae and C. nigoni by phenotyping a large collection of C. nigoni strains each carrying a C. briggsae introgression. In this study, we investigate the genetic mechanism of asymmetric sterility and inviability in both hybrid male and female progeny between the two species. Specifically, we performed reciprocal crosses between C. briggsae and different C. nigoni strains that each carries a GFP-labeled C. briggsae genomic fragment referred to as introgression, and scored the HI phenotypes in the F1 progeny. The aggregated introgressions cover 94.6% of the C. briggsae genome, including 100% of the X chromosome. Surprisingly, we observed that two C. briggsae X fragments that produce C. nigoni male sterility as an introgression rescued hybrid F1 sterility in males fathered by C. briggsae, indicating that at least two separate X-autosome interactions are involved in the hybrid male sterility. In addition, we identified another two C. briggsae genomic intervals on the Chromosome II or IV, respectively, which can rescue the inviability, but not the sterility, of hybrid F1 males fathered by C. nigoni, suggesting the involvement of differential epistatic interactions in the asymmetric hybrid male fertility and inviability. Importantly, backcrossing of the rescued sterile males with C. nigoni led to isolation of a 1.1-Mb genomic interval that specifically interacts with an X-linked introgression, which is essential for hybrid male fertility. We further identified three C. briggsae genomic intervals on the Chromosome I, II and III, respectively that produce inviability in all F1 progeny dependent or independent of the parent-of-origin. Taken together, we identified multiple independent interacting loci that are responsible for asymmetric hybrid male and female sterility and inviability, which provides important insights into the asymmetric HI and lays a foundation for their molecular characterization.


1969 ◽  
Vol 17 (3) ◽  
pp. 515 ◽  
Author(s):  
JA Mccomb

I.fluviatilis occurs in diploid hermaphrodite, tetraploid hermaphrodite, and diploid dioecious populations. Studies of seed production and germination showed significant but incomplete genetic barriers between the various sex and ploid forms. Male and female sterility are controlled by recessive genes which appear to be linked with a recessive sublethal. Interaction between the sex-determining genes results in plants genotypically neuter being phenotypically male. The plants used in the crosses were shown to be heterozygous for at least some of the sex-determining genes and for genes controlling several phenotypic characters not associated with the sex system. Extensive gene hybridity, and consequently heterosis as a component of the genetic system of the species, was also suggested by the observation that the percentage seed germination and seedling survival fell with increased inbreeding. It is concluded that the diploid hermaphrodite, tetraploid hermaphrodite, and diploid dioecious races should be treated as separate subspecies and the female plants from the gynodioecious population as a form of the species.


Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1243-1255 ◽  
Author(s):  
Hope Hollocher ◽  
Chug-I Wu

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.


Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 745-754 ◽  
Author(s):  
Xulio R Maside ◽  
José P Barral ◽  
Horacio F Naveira

Abstract One of the most frequent outcomes of interspecific hybridizations in Drosophila is hybrid male sterility. Genetic dissection of this reproductive barrier has revealed that the number of responsible factors is very high and that these factors are frequently engaged in complex epistatic interactions. Traditionally, research strategies have been based on contrasting introgressions of chromosome segments that produce male sterility with those that allow fertility. Few studies have investigated the phenotypes associated with the boundary between fertility and sterility. In this study, we cointrogressed three different X chromosome segments from Drosophila mauritiana into D. simulans. Hybrid males with these three segments are usually fertile, by conventional fertility assays. However, their spermatogenesis shows a significant slowdown, most manifest at lower temperatures. Each of the three introgressed segments retards the arrival of sperm to the seminal vesicles. Other small disturbances in spermatogenesis are evident, which altogether lead to an overall reduction in the amount of motile sperm in their seminal vesicles. These results suggest that a delay in the timing of spermatogenesis, which might be brought about by the cumulative action of many different factors of minor segment, may be the primary cause of hybrid male sterility.


Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 789-796 ◽  
Author(s):  
Kyoichi Sawamura ◽  
John Roote ◽  
Chung-I Wu ◽  
Masa-Toshi Yamamoto

Abstract Recent genetic analyses of closely related species of Drosophila have indicated that hybrid male sterility is the consequence of highly complex synergistic effects among multiple genes, both conspecific and heterospecific. On the contrary, much evidence suggests the presence of major genes causing hybrid female sterility and inviability in the less-related species, D. melanogaster and D. simulans. Does this contrast reflect the genetic distance between species? Or, generally, is the genetic basis of hybrid male sterility more complex than that of hybrid female sterility and inviability? To clarify this point, the D. simulans introgression of the cytological region 34D-36A to the D. melanogaster genome, which causes recessive male sterility, was dissected by recombination, deficiency, and complementation mapping. The 450-kb region between two genes, Suppressor of Hairless and snail, exhibited a strong effect on the sterility. Males are (semi-)sterile if this region of the introgression is made homozygous or hemizygous. But no genes in the region singly cause the sterility; this region has at least two genes, which in combination result in male sterility. Further, the males are less fertile when heterozygous with a larger introgression, which suggests that dominant modifiers enhance the effects of recessive genes of male sterility. Such an epistatic view, even in the less-related species, suggests that the genetic complexity is special to hybrid male sterility.


Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 217-226 ◽  
Author(s):  
Daniel A Barbash ◽  
Michael Ashburner

Abstract Hybrid daughters of crosses between Drosophila melanogaster females and males from the D. simulans species clade are fully viable at low temperature but have agametic ovaries and are thus sterile. We report here that mutations in the D. melanogaster gene Hybrid male rescue (Hmr), along with unidentified polymorphic factors, rescue this agametic phenotype in both D. melanogaster/D. simulans and D. melanogaster/D. mauritiana F1 female hybrids. These hybrids produced small numbers of progeny in backcrosses, their low fecundity being caused by incomplete rescue of oogenesis as well as by zygotic lethality. F1 hybrid males from these crosses remained fully sterile. Hmr+ is the first Drosophila gene shown to cause hybrid female sterility. These results also suggest that, while there is some common genetic basis to hybrid lethality and female sterility in D. melanogaster, hybrid females are more sensitive to fertility defects than to lethality.


Genetics ◽  
2002 ◽  
Vol 161 (1) ◽  
pp. 157-170 ◽  
Author(s):  
D Adam Mason ◽  
Robert J Fleming ◽  
David S Goldfarb

Abstract Importin α’s mediate the nuclear transport of many classical nuclear localization signal (cNLS)-containing proteins. Multicellular animals contain multiple importin α genes, most of which fall into three conventional phylogenetic clades, here designated α1, α2, and α3. Using degenerate PCR we cloned Drosophila melanogaster importin α1, α2, and α3 genes, demonstrating that the complete conventional importin α gene family arose prior to the split between invertebrates and vertebrates. We have begun to analyze the genetic interactions among conventional importin α genes by studying their capacity to rescue the male and female sterility of importin α2 null flies. The sterility of α2 null males was rescued to similar extents by importin α1, α2, and α3 transgenes, suggesting that all three conventional importin α’s are capable of performing the important role of importin α2 during spermatogenesis. In contrast, sterility of α2 null females was rescued only by importin α2 transgenes, suggesting that it plays a paralog-specific role in oogenesis. Female infertility was also rescued by a mutant importin α2 transgene lacking a site that is normally phosphorylated in ovaries. These rescue experiments suggest that male and female gametogenesis have distinct requirements for importin α2.


Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 987-997 ◽  
Author(s):  
Bryan Kindiger

Cytogenetic investigations of meiosis in hybrids between maize and Tripsacum have been well documented; however, the inherent problem of male and female sterility has not been addressed either on a genetic or cytogenetic level. The purpose of this cytological study was to identify some of the probable causes of male sterility in maize × Tripsacum dactyloides hybrids. Disturbances in pollen development of maize × T. dactyloides hybrids, derived from both diploid (2n) and tetraploid (4n) Tripsacum sources, were commonly observed. Anomalies in the development of the microspore apparently occurred because of a failure of the chromosomes to congregate at the metaphase plate, development of a tripolar spindle, and failure of cytokinesis at the first and second meiotic divisions. Phenotypic features of abnormal microspore development were the maturation of large pollen grains, "Siamese" pollen grains, the occurrence of variable invaginations, and a nuclear budding-type behavior. These abnormalities were not observed in the 56-chromosome amphidiploid or the 38-chromosome backcross generations.Key words: maize, Tripsacum, microspore, sterility.


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