Asexual reproduction leads to harmful genetic mutations

lizard

Goldteju Tupinambis teguixin. Credit: Wikipedia/CC BY-SA 3.0

A team led by biologists at the University of Texas at Arlington has published a study that supports the theory that species that reproduce asexually have more harmful genetic mutations than those that use sexual reproduction.

Jose Maldonado, a doctoral student in biology from the University of Utah, is the lead author of the new paper titled “Phenogenesis Doubles the Rate of Amino Acid Replacement in the Mitochondrial Whiptail.” Posted in May in has evolvedthe leading journal of evolutionary biology.

Co-authors include T.J. Fernino, a postdoctoral researcher at the University of Denver who received his Ph.D. from UTA in 2020; Alexander Hall, Product Applications Specialist at Thermo Fisher Scientific and Ph.D. from UTA in 2016; Matt Fujita, associate professor of biology at the University of Utah, is Maldonado’s faculty advisor and previously served in the same position at Fernino and Hull.

Parthenogenesis is a natural form of asexual reproduction in which the growth and development of embryos occurs without fertilization by sperm. It is generally believed that sexual reproduction does less harm genetic mutations of asexual reproduction.

In their new study, Maldonado and colleagues tested this theory by studying Aspidoscelis, a genus of whiptail lizards. Due to the abundance and distribution of these reptiles throughout the southwestern United States and northern Mexico, these reptiles are an excellent model system for studying basic cellular mechanisms. parthenogenesis and genetic consequences of asexuality.

The team used whole mitochondrial genome data from asexual and sexual whiptail lizards to investigate their predictions that genetic lineages accumulate mutations faster than sexual lineages.

“Our study shows that when whip-tailed lizards transition from sexual to asexual reproduction, an accumulation of harmful mutations in the mitochondrial genome follows,” Maldonado said. “If asexuals accumulate more harmful mutations than their sexual counterparts, as our findings show, this may explain why asexual reproduction rare in nature and why sex is the predominant form of reproduction in the natural world”.

The team sampled multiple collections of both asexual and sexual whiptail species throughout the southwestern United States and received additional tissue samples from collections at the Burke Museum of Natural History and Culture in Seattle and the American Museum of Natural History in New York City.

Their research showed that transition to asexuality led to a relaxation of natural selection in reproductive lizards and the accumulation of non-synonymous mutations, which alter protein sequence of the gene are often exposed to natural selection. They wrote that this supports previous theoretical predictions that “the loss of sex should lead to an irreversible accumulation of deleterious mutations due to the low efficiency of selection purification, and sex facilitates removal of deleterious mutations.”

“The main finding of our study is that asexual vertebrates, or at least these lizards, accumulate amino acid substitutes, which can be harmful to the organism, at a much higher rate than the sexual species,” Fernino said. This is important because there is a paradox that sexual reproduction is much more expensive, but this is the predominant form of reproduction.”


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more information:
Jose A. Maldonado et al, Parthenogenesis doubles the rate of amino acid replacement in the whiptail mitochondria, has evolved (2022). DOI: 10.1111 / evo.14509

the quote: Asexual Reproduction Leads to Harmful Gene Mutations (2022, August 1) Retrieved August 1, 2022 from https://phys.org/news/2022-08-asexual-reproduction-genetic-mutations.html

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