BGU researchers have determined for the first time the best candidate
genetic mutations for how mammals and birds became warm-blooded. Their findings
were published recently in Nature Ecology & Evolution.
The researchers searched
for the best candidate functional mutations (changes in the genome with an impact)
that independently re-occurred during evolution, and hence were the best
candidates to explain the independent emergence in unrelated groups of species.
This process is a well-known phenomenon in evolution and is called 'convergent
evolution' (such as the emergence of wings in bats and birds), which lack a
good molecular explanation.
The researchers
identified, for the first time, the entire repertoire of such 'convergent'
mutations throughout the evolution of reptiles, birds and mammals (300 million
years of evolution). Then they took the research a step further and asked
whether these mutations could explain a known convergent evolution event. Since
they found that most convergent mutations independently occurred in birds and
mammals, they asked themselves which trait was independently formed in these
two groups of species, and they immediately tested 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.
The first 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
Department of Life Sciences and Dr. Liron Levin.
Prof. Mishmar heads
BGU’s Center of Evolutionary Genomics and Medicine.
This study was funded by
research grants from the Israeli Science Foundation, the Binational Science
Foundation and a US Army Life Science division grant.
