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Genetics. 2016 May;203(1):283-98. doi: 10.1534/genetics.115.186270. Epub 2016 Feb 26.

Host Mitochondrial Association Evolved in the Human Parasite Toxoplasma gondii via Neofunctionalization of a Gene Duplicate.

Author information

1
Department of Biological Sciences, Kenneth P. Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260.
2
Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305.
3
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, VP8 5C2, Canada.
4
Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, US Department of Agriculture, Beltsville, Maryland 20705.
5
Department of Biological Sciences, Kenneth P. Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 boylej@pitt.edu.

Abstract

In Toxoplasma gondii, an intracellular parasite of humans and other animals, host mitochondrial association (HMA) is driven by a gene family that encodes multiple mitochondrial association factor 1 (MAF1) proteins. However, the importance of MAF1 gene duplication in the evolution of HMA is not understood, nor is the impact of HMA on parasite biology. Here we used within- and between-species comparative analysis to determine that the MAF1 locus is duplicated in T. gondii and its nearest extant relative Hammondia hammondi, but not another close relative, Neospora caninum Using cross-species complementation, we determined that the MAF1 locus harbors multiple distinct paralogs that differ in their ability to mediate HMA, and that only T. gondii and H. hammondi harbor HMA(+) paralogs. Additionally, we found that exogenous expression of an HMA(+) paralog in T. gondii strains that do not normally exhibit HMA provides a competitive advantage over their wild-type counterparts during a mouse infection. These data indicate that HMA likely evolved by neofunctionalization of a duplicate MAF1 copy in the common ancestor of T. gondii and H. hammondi, and that the neofunctionalized gene duplicate is selectively advantageous.

KEYWORDS:

Hammondia hammondi; Neospora caninum; Toxoplasma gondii; gene duplication; neofunctionalization

PMID:
26920761
PMCID:
PMC4858780
DOI:
10.1534/genetics.115.186270
[Indexed for MEDLINE]
Free PMC Article

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