Very interesting read. I always wondered when and how mammals evolved to no longer come from eggs
The evolution of biological structures and functions from existing ones, for example a forearm from a fish fin, has been studied for centuries. But how do entirely new things evolve? It’s a tricky question to answer, but Vincent Lynch, PhD, assistant professor of human genetics at the University of Chicago, and his colleagues shed some light on this process in a new study published online today in Cell Reports.
Taking a look at the origins of pregnancy in mammals, they identified large-scale genetic changes that marked the transition from egg laying to live birth. The researchers found thousands of genes that evolved to be turned on or off in the uterus in early mammals, including many with critical functions in establishing maternal-fetal communication and suppressing the mother’s immune system so that a fetus is not attacked. What was most surprising, however, was what…
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