Supergenes can also complicate the mating process. In some species, supergenes create a reproductive system, effectively having four sexes. For example, a North American bird called the White-throated Sparrow has a supergene, so it has two “morphs” that differ in color and behavior. Not only do men have to find women, they have to find partners from opposite morphs. Otherwise, the offspring either inherit the supergene from both parents or die from not inheriting the supergene. Only chicks that have received ‘balanced lethal’ inheritance of one supergene and one regular segment of the chromosome survive.
Considering such a high price, Verdun says it’s a wonder that supergenes have evolved at all. “The subspecies set will be very difficult to maintain, especially over millions of generations,” she said. “It’s one of the great mysteries of supergenes.” This suggests that it may be the most likely cause of the persistence of
Ironically, one of the mechanisms by which supergenes can be preserved appears to be recombination, a phenomenon that is normally resisted.Her Amanda Larracuente, an evolutionary geneticist at the University of Rochester, and her co-authors documented such a case last April. e-life.
Larracuente was not initially concerned with supergenes or their evolutionary costs. Her focus was on selfish genes, pieces of DNA that multiply within a population without benefiting the host.she was fascinated by the selfish gene separation distortion (SD) occurred in certain fruit flies in Zambia. “It’s a sperm killer,” she explained, but it only kills sperm that don’t have chromosomes. SD.
Somewhere in the last 3,000 years, a version of SD Capturing large pieces of chromosomal DNA to create supergenes known as supergenes SD-evil It has spread to Drosophila populations across Africa. “It’s really the ultimate selfish gene,” Larracuente said.
DNA sequencing and analysis by Larracuente, Daven Presgraves, and their colleagues SD-evil accumulate deleterious mutations, as predicted by the near-total lack of recombination between SD-evil and its sister chromosomes. But the researchers didn’t find as many mutations as they expected.
The reason they found is that sometimes flies inherit two chromosomes. SD-evil—and these two supergenes are similar enough to allow recombination between them. It will be possible.
“At the end of the day, just a little bit of recombination is enough,” Larracuente said. She and her Presgraves are now looking for someone else. SD Hypergenes in wild Drosophila populations as a clue to the more general evolution and impact of hypergenes.
Their results indicate that the refining effect of recombination on the genome is important. The complex traits that the stable and predictable inheritance of hypergenes allow can be invaluable in helping species adapt, but even hypergenes sometimes benefit from mixing things up. You can get
original story Reprinted with permission from Quanta Magazine, an editorially independent publication of Simmons Foundation Its mission is to enhance public understanding of science by covering research developments and trends in mathematics, physics and life sciences.
