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Never settling down: frequent changes in sex chromosomes.

Wei KH, Barbash DA - PLoS Biol. (2015)

Bottom Line: A new study reveals multiple dramatic changes in sex chromosome structure and identity in flies; such transitions are accompanied by a series of genomic events that affect chromosome biology, gene regulation, and sex determination.See the accompanying Research Article.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York.

ABSTRACT
A new study reveals multiple dramatic changes in sex chromosome structure and identity in flies; such transitions are accompanied by a series of genomic events that affect chromosome biology, gene regulation, and sex determination. See the accompanying Research Article.

No MeSH data available.


Related in: MedlinePlus

The dynamic cycle and multiple pathways of sex-chromosome evolution.Heteromorphic sex chromosomes evolve from a pair of autosomes and typically follow a trajectory of X specialization and Y degeneration. New sex chromosomes can evolve by either chromosomal fusions or acquisition of new sex-determination genes. Y and X events are indicated above and below the chromosomes, respectively.
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pbio.1002077.g001: The dynamic cycle and multiple pathways of sex-chromosome evolution.Heteromorphic sex chromosomes evolve from a pair of autosomes and typically follow a trajectory of X specialization and Y degeneration. New sex chromosomes can evolve by either chromosomal fusions or acquisition of new sex-determination genes. Y and X events are indicated above and below the chromosomes, respectively.

Mentions: What about the evolution of the sex chromosomes? Heteromorphic sex chromosomes are thought to evolve from a pair of homologous autosomes (Fig. 1). Differentiation first begins when one of the two homologs acquires a sex-determining gene either through a de novo mutation or transposition from a different chromosome. If a male-determining gene is inserted, the former autosome now becomes a proto–Y chromosome and will reside exclusively in males. Alleles closely linked to the male-determining gene will also be largely restricted to males because they will rarely be separated by recombination. This sex-specific restriction opens the potential for closely linked alleles to evolve phenotypes that are beneficial only to males; some such alleles may even have pleiotropic deleterious phenotypes if expressed in females. Because crossing over would now create recombinant individuals carrying deleterious combinations of genes favoring opposing sexes, selection will favor the further reduction of recombination around the male-determining gene. Suppression of recombination then permits additional accumulation of male-beneficial genes on the proto-Y, and as the formerly homologous chromosomes become more differentiated, recombination becomes suppressed in larger areas.


Never settling down: frequent changes in sex chromosomes.

Wei KH, Barbash DA - PLoS Biol. (2015)

The dynamic cycle and multiple pathways of sex-chromosome evolution.Heteromorphic sex chromosomes evolve from a pair of autosomes and typically follow a trajectory of X specialization and Y degeneration. New sex chromosomes can evolve by either chromosomal fusions or acquisition of new sex-determination genes. Y and X events are indicated above and below the chromosomes, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400077&req=5

pbio.1002077.g001: The dynamic cycle and multiple pathways of sex-chromosome evolution.Heteromorphic sex chromosomes evolve from a pair of autosomes and typically follow a trajectory of X specialization and Y degeneration. New sex chromosomes can evolve by either chromosomal fusions or acquisition of new sex-determination genes. Y and X events are indicated above and below the chromosomes, respectively.
Mentions: What about the evolution of the sex chromosomes? Heteromorphic sex chromosomes are thought to evolve from a pair of homologous autosomes (Fig. 1). Differentiation first begins when one of the two homologs acquires a sex-determining gene either through a de novo mutation or transposition from a different chromosome. If a male-determining gene is inserted, the former autosome now becomes a proto–Y chromosome and will reside exclusively in males. Alleles closely linked to the male-determining gene will also be largely restricted to males because they will rarely be separated by recombination. This sex-specific restriction opens the potential for closely linked alleles to evolve phenotypes that are beneficial only to males; some such alleles may even have pleiotropic deleterious phenotypes if expressed in females. Because crossing over would now create recombinant individuals carrying deleterious combinations of genes favoring opposing sexes, selection will favor the further reduction of recombination around the male-determining gene. Suppression of recombination then permits additional accumulation of male-beneficial genes on the proto-Y, and as the formerly homologous chromosomes become more differentiated, recombination becomes suppressed in larger areas.

Bottom Line: A new study reveals multiple dramatic changes in sex chromosome structure and identity in flies; such transitions are accompanied by a series of genomic events that affect chromosome biology, gene regulation, and sex determination.See the accompanying Research Article.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York.

ABSTRACT
A new study reveals multiple dramatic changes in sex chromosome structure and identity in flies; such transitions are accompanied by a series of genomic events that affect chromosome biology, gene regulation, and sex determination. See the accompanying Research Article.

No MeSH data available.


Related in: MedlinePlus