Temperature preference can bias parental genome retention during hybrid evolution.

Interspecific hybridization can introduce genetic variation that aids in adaptation to new or changing environments. Here, we investigate how hybrid adaptation to temperature and nutrient limitation may alter parental genome representation over time. We evolved Saccharomyces cerevisiae x Saccharomyces uvarum hybrids in nutrient-limited continuous culture at 15°C for 200 generations.

Loss of Heterozygosity Drives Adaptation in Hybrid Yeast.

Hybridization is often considered maladaptive, but sometimes hybrids can invade new ecological niches and adapt to novel or stressful environments better than their parents. The genomic changes that occur following hybridization that facilitate genome resolution and/or adaptation are not well understood. Here, we examine hybrid genome evolution using experimental evolution of de novo interspecific hybrid yeast Saccharomyces cerevisiae × Saccharomyces uvarum and their parentals.

Recombining without Hotspots: A Comprehensive Evolutionary Portrait of Recombination in Two Closely Related Species of Drosophila.

Meiotic recombination rate varies across the genome within and between individuals, populations, and species in virtually all taxa studied. In almost every species, this variation takes the form of discrete recombination hotspots, determined in some mammals by a protein called PRDM9. Hotspots and their determinants have a profound effect on the genomic landscape, and share certain features that extend across the tree of life.

No detectable effect of the DNA methyltransferase DNMT2 on Drosophila meiotic recombination.

Epigenetics is known to be involved in recombination initiation, but the effects of specific epigenetic marks like DNA methylation on recombination are relatively unknown. Studies in Arabidopsis and the fungus Ascobolus immersus suggest that DNA methylation may suppress recombination rates and/or alter its distribution across the genome; however, these patterns appear complex, and more direct inquiries are needed. Unlike other organisms, Drosophila only have one known DNA methyltransferase, DNMT2, which is expressed in the ovaries and historically has been thought to be responsible for limited genomic DNA methylation.

Studying recombination with high-throughput sequencing: an educational primer for use with "fine-scale heterogeneity in crossover rate in the garnet-scalloped region of the Drosophila melanogaster X chromosome".

An article by Singh and colleagues in this issue of GENETICS quantifies variation in recombination rate across a small region of the Drosophila melanogaster genome, providing an opportunity for instructors of genetics to introduce or reinforce important concepts such as recombination and recombination rate variation, genome sequencing, and sequence features of the genome. Additional background information, a detailed explanation of the methods used in this study, and discussion questions are provided.