February 24, 2024

The evolution of live births in snails occurred gradually

Which came first: the chicken or the egg? The question is common and not easy to answer. But one could say that laying eggs (ovaries) has deep roots in evolution and arose before the first animals ventured onto land. But since then there have been many independent transitions to live birth throughout the animal kingdom. Many insects, fish, reptiles and especially mammals now give birth to surviving offspring. The oldest evidence of a live birth to date is a 380-million-year-old fossil of an armored fish. However, it remains unclear what genetic changes are needed to drive this special evolutionary process. An international research team led by Sean Stankowski from the Institute of Science and Technology Austria (ISTA) has now used a marine snail as an example to analyze which regions of the genome contribute to whether individuals lay eggs or give birth to live young. Results Published in the specialized magazine “Al-Ilm”..