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Direct Gamete Sequencing Reveals No Evidence for Segregation Distortion in House Mouse Hybrids.

Corbett-Detig R, Jacobs-Palmer E, Hartl D, Hoekstra H - PLoS ONE (2015)

Bottom Line: However, the evolutionary forces that lead to the accumulation of such incompatibilities between diverging taxa are poorly understood.Segregation distorters are believed to be an important source of Dobzhansky-Muller incompatibilities between hybridizing species of Drosophila as well as hybridizing crop plants, but it remains unclear if these selfish genetic elements contribute to reproductive isolation in other taxa.We then genotyped millions of single nucleotide polymorphisms in these gamete pools and tested for a skew in the frequency of parental alleles across the genome.

View Article: PubMed Central - PubMed

Affiliation: Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America.

ABSTRACT
Understanding the molecular basis of species formation is an important goal in evolutionary genetics, and Dobzhansky-Muller incompatibilities are thought to be a common source of postzygotic reproductive isolation between closely related lineages. However, the evolutionary forces that lead to the accumulation of such incompatibilities between diverging taxa are poorly understood. Segregation distorters are believed to be an important source of Dobzhansky-Muller incompatibilities between hybridizing species of Drosophila as well as hybridizing crop plants, but it remains unclear if these selfish genetic elements contribute to reproductive isolation in other taxa. Here, we collected viable sperm from first-generation hybrid male progeny of Mus musculus castaneus and M. m. domesticus, two subspecies of rodent in the earliest stages of speciation. We then genotyped millions of single nucleotide polymorphisms in these gamete pools and tested for a skew in the frequency of parental alleles across the genome. We show that segregation distorters are not measurable contributors to observed infertility in these hybrid males, despite sufficient statistical power to detect even weak segregation distortion with our novel method. Thus, reduced hybrid male fertility in crosses between these nascent species is attributable to other evolutionary forces.

No MeSH data available.


Related in: MedlinePlus

Average proportion CAST reads in sperm libraries versus liver libraries.Using all males (A), using only CW males (B), and using only WC males (C). Lines indicate the approximate threshold at which we would have 50% power to detect distortion at the alpha = 0.0001 level (see Methods for how this threshold was calculated).
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pone.0131933.g002: Average proportion CAST reads in sperm libraries versus liver libraries.Using all males (A), using only CW males (B), and using only WC males (C). Lines indicate the approximate threshold at which we would have 50% power to detect distortion at the alpha = 0.0001 level (see Methods for how this threshold was calculated).

Mentions: After addressing the possibility of contamination, labeling, and quality issues (see S1 Text, S2 Table), we ran our analysis of the data across all autosomes, excluding regions with evidence for copy-number variations (described in Methods). With the exception of windows on chromosome 16 (see below), we found no windows with a statistically significant signature of SD. The lowest uncorrected p-value for any window (aside from those on chromosome 16) was 0.0224, which is not significant when we corrected for multiple tests. Thus, we did not find evidence for SDs in any of the autosomal genomic regions considered, nor on the X or Y chromosomes (Fig 2).


Direct Gamete Sequencing Reveals No Evidence for Segregation Distortion in House Mouse Hybrids.

Corbett-Detig R, Jacobs-Palmer E, Hartl D, Hoekstra H - PLoS ONE (2015)

Average proportion CAST reads in sperm libraries versus liver libraries.Using all males (A), using only CW males (B), and using only WC males (C). Lines indicate the approximate threshold at which we would have 50% power to detect distortion at the alpha = 0.0001 level (see Methods for how this threshold was calculated).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487504&req=5

pone.0131933.g002: Average proportion CAST reads in sperm libraries versus liver libraries.Using all males (A), using only CW males (B), and using only WC males (C). Lines indicate the approximate threshold at which we would have 50% power to detect distortion at the alpha = 0.0001 level (see Methods for how this threshold was calculated).
Mentions: After addressing the possibility of contamination, labeling, and quality issues (see S1 Text, S2 Table), we ran our analysis of the data across all autosomes, excluding regions with evidence for copy-number variations (described in Methods). With the exception of windows on chromosome 16 (see below), we found no windows with a statistically significant signature of SD. The lowest uncorrected p-value for any window (aside from those on chromosome 16) was 0.0224, which is not significant when we corrected for multiple tests. Thus, we did not find evidence for SDs in any of the autosomal genomic regions considered, nor on the X or Y chromosomes (Fig 2).

Bottom Line: However, the evolutionary forces that lead to the accumulation of such incompatibilities between diverging taxa are poorly understood.Segregation distorters are believed to be an important source of Dobzhansky-Muller incompatibilities between hybridizing species of Drosophila as well as hybridizing crop plants, but it remains unclear if these selfish genetic elements contribute to reproductive isolation in other taxa.We then genotyped millions of single nucleotide polymorphisms in these gamete pools and tested for a skew in the frequency of parental alleles across the genome.

View Article: PubMed Central - PubMed

Affiliation: Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America.

ABSTRACT
Understanding the molecular basis of species formation is an important goal in evolutionary genetics, and Dobzhansky-Muller incompatibilities are thought to be a common source of postzygotic reproductive isolation between closely related lineages. However, the evolutionary forces that lead to the accumulation of such incompatibilities between diverging taxa are poorly understood. Segregation distorters are believed to be an important source of Dobzhansky-Muller incompatibilities between hybridizing species of Drosophila as well as hybridizing crop plants, but it remains unclear if these selfish genetic elements contribute to reproductive isolation in other taxa. Here, we collected viable sperm from first-generation hybrid male progeny of Mus musculus castaneus and M. m. domesticus, two subspecies of rodent in the earliest stages of speciation. We then genotyped millions of single nucleotide polymorphisms in these gamete pools and tested for a skew in the frequency of parental alleles across the genome. We show that segregation distorters are not measurable contributors to observed infertility in these hybrid males, despite sufficient statistical power to detect even weak segregation distortion with our novel method. Thus, reduced hybrid male fertility in crosses between these nascent species is attributable to other evolutionary forces.

No MeSH data available.


Related in: MedlinePlus