Genetic And Molecular Analysis Of Lethal Hybrid Rescue A Major Effect Gene In D Melanogaster D Simulans Hybrid Incompatibility

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Genetic And Molecular Analysis Of Lethal Hybrid Rescue A Major Effect Gene In D Melanogaster D Simulans Hybrid Incompatibility

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Author : Nicholas Joseph Brideau
language : en
Publisher:
Release Date : 2010

Genetic And Molecular Analysis Of Lethal Hybrid Rescue A Major Effect Gene In D Melanogaster D Simulans Hybrid Incompatibility written by Nicholas Joseph Brideau and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.

Post-zygotic hybrid incompatibility (HI) refers to barriers such as sterility and inviability that affect the reproductive success of zygotes from interspecies matings. Although the genetic basis for HI has been studied for decades, very few major-effect genes have been identified. Crosses between Drosophila melanogaster and its sibling species D. simulans produce incompatible hybrids. In the cross of D. melanogaster females to D. simulans males, the F1 daughters are semi-viable but sterile, and the sons are inviable. The D. simulans gene Lethal hybrid rescue (Lhr) was identified as contributing to these incompatibilities, on the basis that loss-of-function mutations suppress hybrid male inviability. I have investigated several properties of Lhr in order to understand how it causes HI. I found that LHR physically interacts with another HI protein, Hybrid male rescue (HMR), as well as heterochromatin proteins HP1 and HP6. Furthermore, LHR directly binds to the chromo-shadow domain of HP1 through a potentially novel HP1-interacting motif. Consistent with binding to HP1, LHR localizes to heterochromatic regions of polytene chromosomes. I have discovered that the pericentric localization of LHR depends on both HP1 and HP5, and that this localization may not be critical for causing hybrid male inviability. It was previously reported that Lhr is evolving rapidly in a manner consistent with positive selection. To understand how the divergence of Lhr affects its functions and interactions, I investigated the properties of other Lhr orthologs. First, I found that the yeast two-hybrid interactions with HMR, HP1 and HP6 are conserved for six additional LHR orthologs, and despite the extensive sequence divergence among LHR orthologs, that the properties of the HP1-interacting domain are also conserved. Second, three LHR orthologs co-localize with HP1 at heterochromatic regions of polytene chromosomes when expressed in D. melanogaster. And finally, I also found that the ability to induce hybrid male lethality, that was previously attributed to only D. simulans Lhr, is conserved for D. melanogaster Lhr. These results demonstrate that despite the extensive sequence divergence among Lhr orthologs, many properties remain conserved. Overall, my work contributes to understanding the function of Lhr in both pure species and in hybrids.

Advances In Genetics

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Author : Jeffrey C. Hall
language : en
Publisher: Elsevier
Release Date : 2007-05-07

Advances In Genetics written by Jeffrey C. Hall and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-05-07 with Science categories.

The field of genetics is rapidly evolving and new medical breakthroughs are occuring as a result of advances in knowledge of genetics. This series continually publishes imporatnt reviews of the broadest interest to geneticists and their colleagues in affiliated disciplines.

Advances In Genetics

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Author :
language : en
Publisher: Academic Press
Release Date : 1997-09-13

Advances In Genetics written by and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997-09-13 with Science categories.

Advances in Genetics increases its focus on modern human genetics and its relation to medicine with the merger of this long-standing serial with Molecular Genetic Medicine. This merger affirms theAcademic Press commitment to publish important reviews of the broadest interest to geneticists and their colleagues in affiliated disciplines.

Cumulated Index Medicus

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Author :
language : en
Publisher:
Release Date : 1993

Cumulated Index Medicus written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993 with Medicine categories.

Proceedings Of The National Academy Of Sciences Of The United States Of America

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Author : National Academy of Sciences (U.S.)
language : en
Publisher:
Release Date : 2003

Proceedings Of The National Academy Of Sciences Of The United States Of America written by National Academy of Sciences (U.S.) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Electronic journals categories.

Genetics Abstracts

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Author :
language : en
Publisher:
Release Date : 1996

Genetics Abstracts written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1996 with Genetics categories.

Bibliography Of Agriculture With Subject Index

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Author :
language : en
Publisher:
Release Date : 1993-11

Bibliography Of Agriculture With Subject Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1993-11 with Agriculture categories.

Agrindex

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Author :
language : en
Publisher:
Release Date : 1994

Agrindex written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1994 with Agriculture categories.

Genetic Molecular Analysis Of Hybrid Incompatibility In Drosophila

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Author : Arundhati Shamoni Maheshwari
language : en
Publisher:
Release Date : 2012

Genetic Molecular Analysis Of Hybrid Incompatibility In Drosophila written by Arundhati Shamoni Maheshwari and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.

Over evolutionary time genomes diverge by acquiring new mutations, some of which isolate species by erecting reproductive barriers. The study of such genes sheds light on how fundamental developmental processes diverge and result in new species. Hybrid incompatibility (HI) genes contribute to speciation by causing the sterility and inviability of interspecific offspring. The Hmr (Hybrid male rescue) and Lhr (Lethal hybrid rescue) genes are a major cause of hybrid lethality between Drosophila melanogaster and its sibling species D. simulans. Hybrid sons from this cross are normally inviable; however by mutating either the D. melanogaster ortholog of Hmr or the D. simulans ortholog of Lhr, viable adult hybrid sons are recovered. Like other HI genes, both Lhr and Hmr are rapidly evolving under selection. In the first study, I asked whether the evolutionary history of selection for Hmr is confined to the hybridizing lineages. I conducted a population genetic survey of Hmr alleles from two sister species D. yakuba and D. santomea, whose common ancestor diverged from the common ancestor of D. melanogaster and D. simulans approximately 10 Myrs ago. I found that Hmr has diverged recurrently under positive selection in multiple independent speciation events, suggesting that Hmr is likely to be functionally diverging in multiple species. In the second study, I examined the molecular nature of functional divergence for the HI gene, Lhr. Strikingly, I found that despite rapid evolution of the Lhr coding sequence, hybrid lethal activity is not a derived function specific to one lineage, but instead a conserved function shared by both Lhr orthologs. Examination of the heterochromatic localization patterns of Lhr orthologs also failed to reveal any evidence of functional divergence. Instead I discovered that regulatory divergence underlies the asymmetric hybrid lethal activities of Lhr orthologs. In the last study, I identified Lhr2, a D. simulans Lhr allele with a highly unusual coding sequence, as a hybrid rescue mutation. I used it to identify a conserved region in the C-terminus of the LHR protein that is critical for hybrid incompatibility. Using the Lhr2 allele I was able to assay the effect of an indel polymorphism that was segregating in the common ancestor of D. melanogaster and D. simulans on hybrid incompatibility. Notably, I found that this indel polymorphism contributes significantly to the functional divergence of Lhr.

Biological Agricultural Index

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Author :
language : en
Publisher:
Release Date : 1995

Biological Agricultural Index written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1995 with Agriculture categories.