Evolution of genes in bat ears

New research conducted by the University of Bristol shows that echolocation can evolve more than once in bats.

Professor Gareth Jones of Bristol University and Dr. Stephen Rossiter of Queen Mary University, London, in collaboration with colleagues from Shanghai's East China Normal University, studied the evolution of a gene called Prestin in bat - mammal with very sensitive hearing at high frequencies

Prestin encodes proteins for outer hair cells - the tiny structure of the inner ear that provides extremely sensitive hearing for this mammal. Important mutations occur when animals are born leading to the evolution of Prestin from similar proteins. There have been controversies about Prestin's slight change when bats evolved

Scientists have studied the ADN Prestin series in sound-locating bats and fruit-free fruit bats. They found that the gene segments evolved similarly in species of bat that are located in sound with distant relations. However, they could not find any evidence of a change in Prestin gene in fruit bats, which is anticipated from the defect of hearing activity at the high frequency of this bat.

If Prestin really helps bats hear echoes at high frequencies, the research results reinforce the notion that sound positioning has evolved more than once in bats. Independent evolution with a distant relative feature is called convergence, the term often used to describe the physical characteristics of species living in similar environments and facing pressure. Selective forces are the same, such as spikes in porcupines. Examples of molecular convergence are rare.

Big ear horseshoe bat Rhinolophus macrotis (Photo: Professor Gareth Jones).

Professor Jones and Dr. Rossiter said: 'If listening is an Olympic subject, the bat species located by sound will be a good candidate for the medal. Their ears can hear sounds at higher frequencies than any mammal because they need to hear the sound reverberating from the ultrasound they emit '.

'In recent years, scientists have discovered the interesting fact that bats that locate sound without groups together in evolutionary trees, instead, some have close relatives. closer to relatives who do not locate by sound, fruit bat species. This raises the question that bat sound locating evolves more than once or that fruit bats lose their ability to locate sound. '

'Evolutionary biologists have long conceived that morphological similarities do not reflect the evolutionary relationships between animals because of the phenomenon of convergent evolution. The same life can make animals with distant relatives become very similar when they live in the same environment and natural selection will bring about the same results '.

'The same thing seems to be true for gene sequences - the need to locate sounds can cause genes to grow in the same structure. Our research shows that scientists should be cautious when making conclusions about evolutionary relationships based on genetics. Because genes are able to participate in important functions, they can also be formed by convergent evolution. '

Refer:
Gang Li, Jinhong Wang, Stephen J. Rossiter, Gareth Jones, James A. Cotton, and Shuyi Zhang.The hearing gene Prestin reunites echolocating bats.PNAS, (in press)