Journal Article

Birth-and-Death of <i>KLK3</i> and <i>KLK2</i> in Primates: Evolution Driven by Reproductive Biology

Patrícia Isabel Marques, Rui Bernardino, Teresa Fernandes, Eric D. Green, Belen Hurle, Victor Quesada and Susana Seixas

in Genome Biology and Evolution

Published on behalf of Society for Molecular Biology and Evolution

Volume 4, issue 12, pages 1331-1338
Published in print January 2012 |
Published online November 2012 | e-ISSN: 1759-6653 | DOI:

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The kallikrein (KLK) gene family comprises the largest uninterrupted locus of serine proteases in the human genome and represents a notable case for studying the evolutionary fate of duplicated genes. In primates, a recent duplication event gave rise to KLK2 and KLK3, both encoding essential proteins for the cascade of seminal plasma liquefaction. We reconstructed the evolutionary history of KLK2 and KLK3 by comparative analysis of the orthologous sequences from 22 primate species, calculated dN/dS ratios, and addressed the hypothesis of coevolution with their substrates, the semenogelins (SEMG1 and SEMG2). Our findings support the placement of the KLK2–KLK3 duplication in the Catarrhini ancestor and unveil the frequent loss of KLK2 throughout primate evolution by different genomic mechanisms, including unequal crossing-over, deletions, and pseudogenization. We provide evidences for an adaptive evolution of KLK3 toward an expanded enzymatic spectrum, with an effect on the hydrolysis of semen coagulum. Furthermore, we found associations between mating system, the number of SEMG repeat units, and the number of functional KLK2 and KLK3, suggesting complex evolutionary dynamics shaped by reproductive biology.

Keywords: serine proteases; adaptive evolution; mating system; semen coagulation; semenogelins

Journal Article.  4242 words.  Illustrated.

Subjects: Bioinformatics and Computational Biology ; Evolutionary Biology ; Genetics and Genomics

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