Sex chromosomes have a large effect on reproductive isolation and play an important role in hybrid inviability. In Drosophila hybrids, X-linked genes have pronounced deleterious effects on fitness in male hybrids, which have only one X chromosome. Several studies have succeeded at locating and identifying recessive X-linked alleles involved in hybrid inviability. Nonetheless, the density of dominant X-linked alleles involved in interspecific hybrid viability remains largely unknown. In this report, we study the effects of a panel of small fragments of the D. melanogaster X-chromosome carried on the D. melanogaster Y-chromosome in three kinds of hybrid males: D. melanogaster/D. santomea, D. melanogaster/D. simulans and D. melanogaster/D. mauritiana. D. santomea and D. melanogaster diverged over 10 million years ago, while D. simulans (and D. mauritiana) diverged from D. melanogaster over 3 million years ago. We find that the X-chromosome from D. melanogaster carries dominant alleles that are lethal in mel/san, mel/sim, and mel/mau hybrids, and more of these alleles are revealed in the most divergent cross. We then compare these effects on hybrid viability with two D. melanogaster intraspecific crosses. Unlike the interspecific crosses, we found no X-linked alleles that cause lethality in intraspecific crosses. Our results reveal the existence of dominant alleles on the X-chromosome of D. melanogaster which cause lethality in three different interspecific hybrids. These alleles only cause inviability in hybrid males, yet have little effect in hybrid females. This suggests that X-linked elements that cause hybrid inviability in males might not do so in hybrid females due to differing sex chromosome interactions.
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http://dx.doi.org/10.1371/journal.pgen.1004270 | DOI Listing |
Int J Biol Macromol
December 2024
National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China. Electronic address:
The ABORTED MICROSPORES (AMS) gene is crucial for tapetal cell development and pollen formation, but its role in Upland cotton (Gossypium hirsutum) has not been previously documented. This study identified GhAMS11 as a key transcription factor, with its high expression specifically observed during the S4-S6 stages of anther development, a critical period for tapetal activity and pollen formation. Subcellular localization confirmed that GhAMS11 was located in the nucleus.
View Article and Find Full Text PDFFly (Austin)
December 2025
Centre for Biological Diversity, School of Biology, University of St Andrews, St Andrews, UK.
and are a sister species pair that have been used as a model for studies of reproductive isolation and speciation for almost 100 years owing to their close evolutionary history, well characterized genetic differences, and overlapping geographic distribution. There are extensive analyses of both pre- and post-zygotic isolation, including studies of courtship divergence, conspecific sperm precedence (CSP) and how reinforcement by natural selection may or may not act to strengthen isolation in sympatry. Post-zygotic analyses explore the underlying mechanics of reproductive isolation; how inversions may give rise to initial speciation events and misexpression of key genes typically found within inversion regions render hybrid offspring unfit or inviable.
View Article and Find Full Text PDFPlants (Basel)
November 2024
Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
The angiosperm seed represents a critical evolutionary breakthrough that has been shown to propel the reproductive success and radiation of flowering plants. Seeds promote the rapid diversification of angiosperms by establishing postzygotic reproductive barriers, such as hybrid seed inviability. While prezygotic barriers to reproduction tend to be transient, postzygotic barriers are often permanent and therefore can play a pivotal role in facilitating speciation.
View Article and Find Full Text PDFbioRxiv
October 2024
Department of Ecology, Behavior, and Evolution, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
Intrinsic reproductive isolation occurs when genetic differences between populations disrupt the development of hybrid organisms, preventing gene flow and enforcing speciation. While prior studies have examined the genetic origins of hybrid incompatibility, the effects of incompatible factors on development remain poorly understood. Here, we investigate the mechanistic basis of hybrid incompatibility in nematodes by capitalizing on the ability of females to produce embryos after mating with males from several other species.
View Article and Find Full Text PDFJ Dairy Sci
January 2025
Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810001, China; University of Chinese Academy of Sciences, Beijing 100049, China; Qinghai Key Laboratory of Animal Ecological Genomics, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, Qinghai 810001, China. Electronic address:
Hybrids between closely related but genetically incompatible species are often inviable or sterile. Cattle-yak, an interspecific hybrid of yak and cattle, exhibits male-specific sterility, which limits the fixation of its desired traits and prevents genetic improvement in yak through crossbreeding. Transcriptome profiles of testicular tissues have been generated in cattle, yak, and cattle-yak; however, the genetic variations underlying differential gene expression associated with hybrid sterility have yet to be elucidated.
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