Rapid Expansion and Functional Divergence of Subtelomeric Gene Families in Yeasts

• Published in: Current biology Vol. 20; no. 10; pp. 895 - 903
• Main Authors: Brown, Chris A., Murray, Andrew W., Verstrepen, Kevin J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 25.05.2010
• Subjects: Adaptations; Animals; Base Sequence; Biological Evolution; DNA; EVO_EVOL; Genome, Fungal; Markov Chains; Molecular Sequence Data; Multigene Family - genetics; Phylogeny; Telomere; Yeasts - classification; Yeasts - genetics; EVO_EVOL; DNA
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2010.04.027

Subtelomeres, regions proximal to telomeres, exhibit characteristics unique to eukaryotic genomes. Genes residing in these loci are subject to epigenetic regulation and elevated rates of both meiotic and mitotic recombination. However, most genome sequences do not contain assembled subtelomeric sequences, and, as a result, subtelomeres are often overlooked in comparative genomics. We studied the evolution and functional divergence of subtelomeric gene families in the yeast lineage. Our computational results show that subtelomeric families are evolving and expanding much faster than families that do not contain subtelomeric genes. Focusing on three related subtelomeric MAL gene families involved in disaccharide metabolism that show typical patterns of rapid expansion and evolution, we show experimentally how frequent duplication events followed by functional divergence yield novel alleles that allow the metabolism of different carbohydrates. Taken together, our computational and experimental analyses show that the extraordinary instability of eukaryotic subtelomeres supports rapid adaptation to novel niches by promoting gene recombination and duplication followed by functional divergence of the alleles. ► Subtelomeric gene families are evolving faster than nonsubtelomeric gene families ► Subtelomeres are enriched for niche-specific genes and devoid of housekeeping genes ► Duplications of subtelomeric genes promote functional divergence ► Subtelomeres support rapid evolution and adaptation