Scientists in Germany began to study whales and dolphins and piece together what made them go from land living creatures to water inhabitants about 50 million years ago. They studied the DNA and gene differences between modern day whales and hippos, which are the closest ancestors to 'land living whales' or land living cetaceans. The study found that whales actually "lost" as many as 85 genes that affected physical processes that would be a burden in full time water life. One example dealt with the POLM genes, which regulate the repair of DNA, but is also very damage prone. This is important because DNA gets damaged with cycles of high to low oxygen. So getting rid of an inefficient protein would only help them make that transition from land to sea. Another gene that was lost was SLC4A9, which regulated saliva production. Saliva helps break down food, which unnecessary in water. Also, less saliva helps keep fresh water in the body. This gene would be beneficial to lose in the water.
I think this article really highlights how the environments affects both evolution and genetics. Simply changing environments completely changes how an animal operates and lives. It is important to see how environmental changes affected animals in the past and predict how they can impact others in the future.
https://www.sciencenews.org/article/losing-genes-may-have-helped-whale-ancestors-adapt-life-underwater
https://www.inverse.com/article/59582-whales-and-dolphins-lost-genes-tell-their-story
I've genuinely never thought of the evolution of a dolphin or whale and thats actually really interesting to think about how they were once land creatures, much less hippos. Even more interesting, is the fact that they were able to "lose" genes in order to adapt to the new environment. The process kind of reminds me of autoimmune disease because its attacking or damaging itself. Overall, very interesting article!
ReplyDeleteI find this a really interesting article as I never really thought that whales were ever one of the organisms that migrated to land in the first place. to find out that it once lived on land, shares DNA with hippos and even lost so much of its genetic material to adapt to life under water is astonishing.
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