Paris (AFP) \u2013 From an evolutionary perspective, sexual reproduction could be seen as a non-starter.<\/p>\n
Compared to cloning, which also exists in Nature, it\u2019s a major waste of time and energy.<\/p>\n
Think of the ungainly, preening peacock \u2014 an easy snack for tigers and wild dogs \u2014 strutting his stuff to impress the ladies.<\/p>\n
Even without predators, sex and its attendant rituals can be dangerous: when stags butt heads or alpha-male lions fight for mating rights, it does not always end well.<\/p>\n
Some animals and plants \u2014 starfish, bananas, to name two \u2014 reproduce asexually. Even a few birds and bees do it solo, Cole Porter be damned.<\/p>\n
Others, like the Komodo dragon, can work it either way, though asexually produced Komodo babies \u2014 produced by their mothers \u2014 are not clones.<\/p>\n
In short, without males in the picture the business of reproducing is faster and less fraught.<\/p>\n
And yet, sex remains by far the dominant means by which the world\u2019s fauna and flora pass on genes to future generations, ensuring the survival of the species.<\/p>\n
\u201cOne of the oldest questions in evolutionary biology is, why does sex exist?\u201d, said Stuart Auld, a biologist at the University of Stirling in Scotland.<\/p>\n
Darwin\u2019s laws of natural selection dictate that doing it the hard way \u2014 sex rather than cloning, in this case \u2014 must confer some major, if hidden, advantages.<\/p>\n
Granted, sexual reproduction fuels genetic variation, which boosts the likelihood that offspring in the wild will have the genetic makeup to thrive in an ever-changing environment.<\/p>\n
By contrast, clones do not vary, and so if the environment deteriorates, a clonal mother will produce offspring that lack the genes they need to succeed.<\/p>\n
\u2013 \u2018Twofold cost of sex\u2019 \u2013<\/p>\n
\u201cBut sex needs to be over twice as efficient as cloning to outweigh its costs,\u201d Auld told AFP.<\/p>\n
\u201cIf sex is to be favoured by natural selection, a sexual mother needs to either produce twice as many offspring as an asexual mother, or produce offspring that are twice as good.\u201d<\/p>\n
Biologists have long agreed that the enhanced ability to fight off disease was a major advantage of the genetic changes that come with sexual reproduction.<\/p>\n
But constructing an experiment to confirm this has always proved difficult: how do you compare the costs and benefits of sexual strategies in different species?<\/p>\n
To get around that \u201capples and oranges\u201d problem, Auld and two colleagues used an organism \u2014 the humble waterflea \u2014 that can reproduce both ways.<\/p>\n
\u201cBy comparing clonal and sexual daughters from the same mothers, we found sexually produced offspring get less sick,\u201d Auld said.<\/p>\n
The ever-present need to evade disease, it turned out, explains why sex persists in the natural world in spite of the high \u201ccosts\u201d that come with it, he explained.<\/p>\n
Parasites and their hosts are in a constant tug-of-war, each evolving and adapting to the other, one attacking immune defences and the other rebuilding them.<\/p>\n
Cloning offers fewer chances for genetic changes in the host that can rise to that challenge.<\/p>\n
But sexual reproduction \u2014 with a new genetic variations coming into the mix with each generation \u2014 offers more opportunities to fight back against pathogens.<\/p>\n
The findings were published in the British journal Proceedings of the Royal Society B.<\/p>\n","protected":false},"excerpt":{"rendered":"
Paris (AFP) \u2013 From an evolutionary perspective, sexual reproduction could be seen as a non-starter. Compared to cloning, which also exists in Nature, it\u2019s a major waste of time and energy. Think of the ungainly, preening peacock \u2014 an easy snack for tigers and wild dogs \u2014 strutting his stuff to impress the ladies. Even […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-60148","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts\/60148","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/comments?post=60148"}],"version-history":[{"count":0,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts\/60148\/revisions"}],"wp:attachment":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/media?parent=60148"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/categories?post=60148"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/tags?post=60148"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}