Showing posts with label Mediterranean. Show all posts
Showing posts with label Mediterranean. Show all posts

Australian and Mediterranean Great White Shark Evolution

Luck plays a large part in evolution. Climate suddenly changes and if by chance a species of animal carries suitable genes to flourish in the new environment that animal lives on. Other species die off because they cannot cope.

New findings about the great white shark highlights this. Australian great whites and the Mediterranean type have genes that point to common ancestry. It is believed that a few related female sharks split up. Some going north to the Mediterranean from the larger gene pool in the south, or they peeled off from the main group in the Atlantic some going north the others going south. Narrow channels in the Mediterranean stopped this group from rejoining the Australian gene pool.

This happened 450,000 years ago. Mutations since that time make the timeline clear. It is believed that swordfish and tuna the main food of the great white also split off from the their main groups. Great white sharks followed the food supply.
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Australian Blog                         

Agriculture Was Brought into Western Europe by Southern European Males

Learning has not been linear for human beings. Advancement can be different from one place to another. It is now known from DNA analysis of 5,000 year old skeletons in a French cave that women did not travel into western Europe. Mitochondrial DNA is passed down only from the mother which shows that European women had local ancestry. On the other hand the Y chromosome passed down through males shows movement of males into new European regions. Knowledge of farming came into new areas when the males moved in and mated with local females.

Analysis of DNA from 29 skeletons found in France, highlighted this difference between the mitochondrial DNA and Y chromosome. Males had moved from the Mediterranean to western Europe. Most of the males in the 29 skeleton group were related, so when the males arrived they stayed on the land with their new hunter gatherer wives.

The southern males had a problem: they did not have the lactose tolerant gene of central Europeans. They had to drink fermented milk from sheep and goats. Adult central European males could easily digest milk from cows.

More work is being done to further clarify how and when agriculture spread across Europe.
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