Value of Sexual Reproduction Versus Asexual Reproduction
ScienceDaily (Jan. 25, 2010) — Living organisms have good reason for engaging in sexual, rather than asexual, reproduction according to Maurine Neiman, assistant professor of biology in the UI College of Liberal Arts and Sciences and researcher in the Roy J. Carver Center for Genomics.
The study looked at sexual, as well as asexual, varieties of a New Zealand freshwater snail, Potamopyrgus antipodarum, by sequencing mitochondrial genomes and found that the sexually reproducing snails had accumulated harmful DNA mutations at about half the rate of the asexual snails. (Credit: Image courtesy of University of Iowa)
The study looked at sexual, as well as asexual, varieties of a New Zealand freshwater snail (left), Potamopyrgus antipodarum, by sequencing mitochondrial genomes and found that the sexually reproducing snails had accumulated harmful DNA mutations at about half the rate of the asexual snails.
...
+++++
Molecular Biology and Evolution, doi:10.1093/molbev/msp300
Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater SnailMaurine Neimana, Gery Hehmana, Joseph T. Millera,b,John M. Logsdon, Jr.a and Douglas R. Taylorc
a Department of Biology and Roy J. Carver Center for Comparative Genomics, University of Iowa, Iowa City, IA, 52242, USA
b Centre for Plant Biodiversity Research, CSIRO Plant Industry, Canberra, ACT, 2601, Australia
c Department of Biology, University of Virginia, Charlottesville, VA, 22903, USA
Corresponding author: M. Neiman, Phone: 319-384-1814; maurine-neiman@uiowa.edu
Received for publication July 24, 2009. Revision received November 29, 2009. Accepted for publication December 2, 2009.
Sexual reproduction is both extremely costly and widespread relative to asexual reproduction, meaning that it must also confer profound advantages in order to persist. One theorized benefit of sex is that it facilitates the clearance of harmful mutations, which would accumulate more rapidly in the absence of recombination. The extent to which ineffective purifying selection and mutation accumulation are direct consequences of asexuality, and whether the accelerated buildup of harmful mutations in asexuals can occur rapidly enough to maintain sex within natural populations, however, remain as open questions. We addressed key components of these questions by estimating the rate of mutation accumulation in the mitochondrial genomes of multiple sexual and asexual representatives of Potamopyrgusantipodarum, a New Zealand snail characterized by mixed sexual/asexual populations. We found that increased mutation accumulation is associated with asexuality and occurs rapidly enough to be detected in recently-derived asexual lineages of P. antipodarum. Our results demonstrate that increased mutation accumulation in asexuals can differentially affect coexisting and ecologically similar sexual and asexual lineages. The accelerated rate of mutation accumulation observed in asexual P. antipodarum provides some of the most direct evidence to date for a link between asexuality and mutation accumulation, and implies that mutational buildup could be rapid enough to contribute to the short-term evolutionary mechanisms that favor sexual reproduction.
Key Words: Sex • asexual • parthenogenetic • Muller's ratchet • mtDNA • Hill-Robertson • Potamopyrgus antipodarum
+++++
Professores, pesquisadores e alunos de universidades públicas e privadas com acesso ao site CAPES/Periódicos podem ler gratuitamente este artigo da Molecular Biology and Evolution e de mais 15.000 publicações científicas.
