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Repeated evolution: air bladders or lungs in different groups of fishes evolved multiple times
Stuff happens …. Several times throughout their radiation fish have evolved either lungs or swim bladders as gas-holding structures. Lungs and swim bladders have different ontogenetic origins and can be used either for buoyancy or as an accessory respiratory organ. Therefore, the presence of air-filled bladders or lungs in different groups of fishes is an […]
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Repeated evolution: Appendix evolved more than 30 times!
The appendix may not be useless after all. The worm-shaped structure found near the junction of the small and large intestines evolved 32 times among mammals, according to a new study. The finding adds weight to the idea that the appendix helps protect our beneficial gut bacteria when a serious infection strikes. Now get ready […]
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Repeated evolution: Sex chromosomes evolved independently, many times, in various species
Sex chromosomes evolved not once, but many times, independently … stuff happens … Sex chromosomes are derived from autosomes and have evolved independently many times in different lineages. For example, the human X and Y chromosomes originated about 200-300 million years ago in eutherian mammals after the split of monotremes, and sex chromosomes evolved independently […]
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Repeated evolution: Penis-baculum evolved multiple times and have been lost multiple times
Several hypotheses for the function of the baculum have been proposed which lead to testable predictions in a comparative framework. Unfortunately, comparative studies have failed to yield general and consistent results Here, we specifically test this hypothesis by modeling the presence/absence of bacula of 954 mammalian species across a well-established phylogeny and show that the […]
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Repeated evolution of blood types
interesting stuff happened here … or perhaps not ? The ABO histo-blood group, the critical determinant of transfusion incompatibility, was the first genetic polymorphism discovered in humans. Remarkably, ABO antigens are also polymorphic in many other primates, with the same two amino acid changes responsible for A and B specificity in all species sequenced to […]
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Evolution does repeat itself after all: How evolution lets stripes come and go
same stuff happened multiple times, independently in various lakes, and at a record speed … Evolution does repeat itself after all: How evolution lets stripes come and go A team of evolutionary biologists discovers the genetic basis for the repeated evolution of color patterns. The findings about the stripes of the especially diverse species of […]
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Repeated evolution: Lactose tolerance arose independently in Africans and Europeans
In January 2007, an international team of researchers led by geneticist Sarah Tishkoff announced that they had uncovered the genetic roots of Africans’ lactose tolerance. Just as in Europe, on this continent, mutations (in this case, probably three) randomly arose, and these happened to have the effect of keeping the lactase gene switched on. https://evolution.berkeley.edu/evolibrary/news/070401_lactose
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Repeated evolution: Among insect 236 families in 18 of 44 orders independently invaded water
just another extreme convergent evolution event … stuff happens … No insects returned to land after adapting to aquatic habits Due to different evolutionary rates or periodical changes in water characteristics, non-adapted terrestrial insects repeatedly invaded the aquatic realm with well adapted hydrobionts. The proposed reason for the lack of land return is the character of numerous aquatic adaptations […]