New Worlds: How did birds and mammals become warm blooded?

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May 14, 2017 02:02

The analysis of 300 million years of evolution and the discovery of the molecular basis of how warm-blooded animals emerged was conducted by Prof. Dan Mishmar and his student Liron Levin.

Yellow Wagtail bird

Yellow Wagtail bird. (photo credit:ITSIK MAROM)

Ben-Gurion University of the Negev researchers in Beersheba have identified the best candidate for the functional genetic mutations that enabled mammals and birds to become warm-blooded. Their findings were published recently in Nature Ecology & Evolution.

The analysis of 300 million years of evolution and the discovery of the molecular basis of how warm-blooded animals emerged was conducted by Prof. Dan Mishmar of the life science department and his student Liron Levin.



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They looked for changes in the genome whose impact re-occurred independently during evolution. These were the best candidates to explain the emergence of characteristics in unrelated groups of species (such as the emergence of wings in bats and birds) that lacked a good molecular explanation. This process is a well-known phenomenon in evolution called “convergent evolution.”

The researchers identified the entire repertoire of such mutations throughout the millions of years of evolution of cold-blooded reptiles (whose temperatures are affected by the environment) and birds and mammals that maintain a steady temperature. Since they found that most convergent mutations occurred independently in birds and mammals, they wondered which common trait was independently formed in these two groups of species. The team immediately tested it to see if it was warm blood.


Indeed, genes involved in the maintenance of blood temperature preferentially accumulated the same mutations independently in birds and mammals, thus providing the first molecular explanation for this evolutionary phenomenon.

ONLINE PHYSICS COURSES MAKE A ‘BIG BANG’

An “evolution” is taking place at Bar-Ilan University’s physics department, with a new program offering three online courses in mechanics, waves and mathematical methods for physicists. They have become such a hit that five additional courses were introduced when the year’s second semester began in mid-March. In total, there are eight courses and two preparatory courses required for acceptance into the department.

“Our mechanics course has been the most popular of all,” said deputy department chairman Dr. Yossi Ben-Zion, who initiated the online courses with chairman Prof. Michael Rosenbluh.

“Nearly 1,000 viewers have watched the course since its debut three months ago, and hundreds have viewed each of the others.” They can be accessed at www.youtube.com/channel/UC-0givyu0TtPTf2cIXZtSjw/playlists.

To film the online classes, a high-quality camera is affixed to a permanent location in the classroom, and the lecturer is fitted with a microphone. The session is then edited and posted on YouTube. All of the courses are open to students and the general public.

The online courses have played a particularly meaningful role in the lives of students who are forced to miss class for a variety of reasons, including IDF reserve duty, maternity leave or illness. Bar-Ilan said that in addition to being taught in the classroom, all BA courses in the department will become available online within the next three years. The department also hopes to launch online courses in English next year. Eventually, they may also be broadcast live.
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