novel hypotheses answer key questions about the evolution of sexual reproduction
Schematic illustration of the advantage of the first sexual individual resulting from the seesaw effect. Possible combinations of the sex allele (S) and non-sex allele (N) entering the clean genome (C) or dirty genome (D) are shown. S (dominant over N) controls meiosis and fusion. The first automictic selfing event is successful with a 50% probability. Credit: Journal of Ethology (2022). DOI: 10.1007/s10164-022-00760-3

The evolution of sexual reproduction in living beings is one of the biggest mysteries in biology. There are two known modes of reproduction: asexual, where the organism creates clones of itself, and sexual, where gametes from two individuals fuse to give rise to progeny. There are many hypotheses that address various aspects of the evolution of sexual reproduction; nonetheless, there are also many questions that are still unanswered.

The biggest question in the study of the evolution of sexual reproduction is the question of cost. Sexual reproduction requires exponentially more energy than asexual reproduction. Nevertheless, sexual reproduction has two major advantages over asexual reproduction: it results in genetic diversity in offspring, and it eliminates harmful mutations.

Associate Professor Eisuke Hasegawa of Hokkaido University and Associate Professor Yukio Yasui of Kagawa University have proposed and modeled two novel hypotheses which address two open questions in the study of the evolution of sexual reproduction. Their hypotheses were published in the Journal of Ethology.

The researchers proposed hypotheses to address the “two-fold cost of sex”: the cost of meiosis and the cost of producing large numbers of male gametes. Sexual reproduction can be isogamous, where the gametes are all of the same size, or it can be anisogamous, where the female gametes are large, while the male gametes are small and numerous. The hypotheses were tested by computer modeling.

The first hypothesis they proposed is the “seesaw effect” by which a large number of harmful mutations are eliminated. The first individual to have a sex-controlling gene—that allowed for meiosis to occur—produced four gametes. Only gametes with the sex-controlling gene could fuse, fixing it in the population and erasing the cost of meiosis. In addition, any harmful mutations were diluted or discarded depending on whether they were associated with the sex-controlling gene.

The second hypothesis, the development of anisogamy via “inflated isogamy,” was developed from the first hypothesis. They suggest that, originally, multicellular organisms with higher energy generation evolved; then, the gamete size increased (“inflated isogamy”) as the increased resources in larger gametes increased the survival rate of offspring. Then, the male gametes reduced in size to fertilize more female gametes—depending on the inflated female gametes to provide the resources for survival. This strategy does not involve any extra cost on the part of the female; in fact, it may have triggered their counteradaptation to the current-day meiosis in females that results in just one female gamete (the oocyte) per gametocyte.

With these hypotheses, the authors have addressed the question of “two-fold cost of sex,” and have also hypothesized that the first sexual reproduction required only one individual, and was a self-fertilizing event. However, the two hypotheses are still in their initial stages, and further work is required to address specific assumptions and conclusions underlying them. More information: Yukio Yasui et al, The origination events of gametic sexual reproduction and anisogamy, Journal of Ethology (2022). DOI: 10.1007/s10164-022-00760-3 Provided by Hokkaido University Citation: Novel hypotheses answer key questions about the evolution of sexual reproduction (2022, August 19) retrieved 19 August 2022 from https://phys.org/news/2022-08-key-evolution-sexual-reproduction.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Keyword: Novel hypotheses answer key questions about the evolution of sexual reproduction

TECH'S NEWS RELATED

Amazon Fire TV Cube: All the New 3rd-Gen Tricks, from 4K Upscaling to Voice Control

The hybrid Alexa device offers native 4K Ultra HD capability and mics for conversing with the Alexa assistant.

View more: Amazon Fire TV Cube: All the New 3rd-Gen Tricks, from 4K Upscaling to Voice Control

Dall-E Opens Its AI Art Creation Tool to Everyone

The artificial intelligence technology can turn text prompts into intriguing illustrations.

View more: Dall-E Opens Its AI Art Creation Tool to Everyone

Multiple-doped hierarchical porous carbons for superior zinc ion storage

(a) Schematic illustration of the fabrication processes of the carbons and the advantages of this method; (b) the nitrogen adsorption/desorption isotherms and (c) the corresponding pore size distribution curves; (d) nitrogen adsorption/desorption isotherms of the carbons obtained from other molecular precursors. Credit: Science China Press Zn-ion hybrid supercapacitors (ZHSCs) ...

View more: Multiple-doped hierarchical porous carbons for superior zinc ion storage

Scientists have a bone to pick with paleontology's portrayal in video games

The representation of Tyrannosaurus rex in COTS video games through time. (a) 3D Monster Maze (1982, J. K. Greye Software). PC. (b) Primal Rage (1994, Midway Games West Inc) Super Nintendo Entertainment System. (c) Tomb Raider (1996, Core Design) PlayStation. (d) The Lost World: Jurassic Park (1997, DreamWorks Interactive) ...

View more: Scientists have a bone to pick with paleontology's portrayal in video games

Scalable and fully coupled quantum-inspired processor solves optimization problems

In a new study, researchers from TUS, Japan, proposed a fully connected scalable annealing processor that, when implemented in FPGA, can easily outperform a modern CPU in solving various combinatorial optimization problems in terms of speed and energy consumption. The proposed method achieves this using an “array calculator,” consisting ...

View more: Scalable and fully coupled quantum-inspired processor solves optimization problems

LHCf continues to investigate cosmic rays

One of the LHCf detectors. Credit: CERN LHCf has completed its first data-taking period during LHC Run 3, taking advantage of the record 13.6 TeV collision energy. This coincides with the machine’s record fill time of 57 hours. Millions of cosmic rays bombard the Earth’s atmosphere every second. These ...

View more: LHCf continues to investigate cosmic rays

Active matter, curved spaces: Mini robots learn to 'swim' on stretchy surfaces

Two small robots move on a stretchy, trampoline-like surface. Credit: Shengkai Li / Hussain Gynai / Georgia Institute of Technology When self-propelling objects interact with each other, interesting phenomena can occur. Birds align with each other when they flock together. People at a concert spontaneously create vortices when they ...

View more: Active matter, curved spaces: Mini robots learn to 'swim' on stretchy surfaces

Regularly Exercising With Weights Linked to Lower Risk of Death

Summary: Regular weight training exercise is associated with a reduced risk of death, a new study reports. Incorporating aerobic exercise with weight-based exercise adds to the protective effect. Source: BMJ Regularly exercising with weights is linked to a lower risk of death from any cause, with the exception of cancer, ...

View more: Regularly Exercising With Weights Linked to Lower Risk of Death

Skill deficit biggest impediment in cloud transformation of Indian entities: IBM Survey

Floridians are livestreaming Hurricane Ian on TikTok

The hidden crisis of England's rural homelessness

Spanish vultures released in Cyprus to replenish population

Musk seeks to lift regulator 'muzzle' on Tesla tweets

Deadpool 3 release date reveal means Wolverine might be in Avengers 5

Google to test disabling Chrome Manifest V2 extensions in June 2023

Eero's Newest Mesh Router Draws Its Power Over Ethernet, No Outlet Necessary

MIT biologist Richard Hynes wins Lasker Award

Larval health of an Antarctic cold-water coral species may be resistant to warming water

You don't have to be a cute koala to be an Instagram influencer. Give lizards and bugs a chance

Are extreme heat waves happening more than expected? Research says not yet

OTHER TECH NEWS

;