scholarly journals Incomplete reproductive isolation and low genetic differentiation despite floral divergence across varying geographic scales in Castilleja

2021 ◽  
Author(s):  
Katherine E. Wenzell ◽  
Angela J. McDonnell ◽  
Norman J. Wickett ◽  
Jeremie B. Fant ◽  
Krissa A. Skogen
Keyword(s):  
Genetic Differentiation ◽  
Reproductive Isolation ◽  
Incomplete Reproductive Isolation

scholarly journals Strong yet incomplete reproductive isolation in Vermivora is not contradicted by other lines of evidence: A reply to Toews et al.

2021 ◽  
Author(s):  
Cody K. Porter ◽  
John L. Confer ◽  
Kyle R. Aldinger ◽  
Ronald A. Canterbury ◽  
Jeffrey L. Larkin ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Incomplete Reproductive Isolation ◽  
Lines Of Evidence

scholarly journals Genome-Wide Regulatory Interactions in the Early Stages of Drosophila Speciation

2020 ◽  
Author(s):  
◽  
Alwyn Clark Go
Keyword(s):  
Reproductive Isolation ◽  
Expression Analysis ◽  
Regulatory Elements ◽  
Specific Expression ◽  
Allele Specific Expression ◽  
Regulatory Interactions ◽  
Early Stages ◽  
Genome Wide ◽  
Allele Specific ◽  
Incomplete Reproductive Isolation

Speciation occurs when reproductive barriers prevent the exchange of genetic information between individuals. A common form of reproductive barrier between species capable of interbreeding is hybrid sterility. Genomic incompatibilities between the divergent genomes of different species contribute to a reduction in hybrid fitness. These incompatibilities continue to accumulate after speciation, therefore, young divergent taxa with incomplete reproductive isolation are important in understating the genetics leading to speciation. Here, I use two Drosophila subspecies pairs. The first is D. willistoni consisting of D. w. willistoni and D. w. winge. The second subspecies pair is D. pseudoobscura, which is composed of D. p. pseudoobscura and D. p. bogotana. Both subspecies pairs are at the early stages of speciation and show incomplete reproductive isolation through unidirectional hybrid male sterility. In this thesis, I performed an exploratory survey of genome-wide expression analysis using RNA-sequencing on D. willistoni and determined the extent of regulatory divergence between the subspecies using allele-specific expression analysis. I found that misexpressed genes showed a degree of tissue specificity and that the sterile male hybrids had a higher proportion of misexpressed genes in the testes relative to the fertile hybrids. The analysis of regulatory divergence between this subspecies pair found a large (66-70%) proportion of genes with conserved regulatory elements. Of the genes showing evidence or regulatory divergence between subspecies, cis-regulatory divergence was more common than other types. In the D. pseudoobscura subspecies pair, I compared sequence and expression divergence and found no support for directional selection driving gene misexpression in their hybrids. Allele-specific expression analysis revealed that compensatory cis-trans mutations partly explained gene misexpression in the hybrids. The remaining hybrid misexpression occurs due to interacting gene networks or possible co-option of cis-regulatory elements by divergent transacting factors. Overall, the results of this thesis highlight the role of regulatory interactions in a hybrid genome and how these interactions could lead to hybrid breakdown by disrupting gene interaction networks.

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