Thursday, 29 March 2012

Human and dolphin genomes


By Charlotte Dudal - 42832845




Humans and dolphins, what do these two animals have in common? You might think that the only thing they could have in common is that they are both mammals. You’re right, but there is a much more interesting fact. Dolphin and human genomes are almost the same. Dr. David Busbee from the Texas A&M University has been involved in a project that studies the genome of dolphins (Kolber, 2010). His team did a number of experiments using hybrid chromosomes combining human and dolphin chromosomes to identify the homologous traits. The results showed that 36 blocks were matching on both species (Fig.1&2). The experiment consisted in “painting” the chromosomes with a fluorescent chemical that would show the homologous traits (Fig.3). Busbee said that he was very surprised when he got to see the results. Because dolphins seem so different animals compared to humans, they live in oceans, eat fish and their physiology is far from ours. However, scientists believe that at some point humans and dolphins came from the same branch of the evolutionary tree. This is shown by the fact that dolphins are mammals that breathe air just like us, so it is believed that initially they were living on land and moved back to the oceans at a later time.
Fig.1: Homologies between human and dolphin chromosomes detected by chromosome painting.
Fig.2: Matrix showing the distribution of conserved chromosome segments between dolphin (left) and human (top).
Fig.3: Painting of dolphin chromosomes with biotinylates human chromosome-specific paints. Yellow are matching traits.

But how is this discovery useful to science and to us? Evans (2010) discussed that because dolphins have such similarity, they are affected by the same toxins and diseases that affect us. For example, they are affected by red tide toxins, chemicals that are present in wastes which we dump in the sea and other toxins that are present in ocean life. Furthermore, not only have dolphins been affected by the same toxins but they also have learned how to fight or block the effects of these dangerous chemicals. So in other words, if we were able to find out how they are able to have immunization to what affects us, we could use this information to cure or fight the diseases that are caused in humans! For example, we could synthetize a vaccine for diseases. Another important fact is that dolphins can fight type 2 diabetes by simply “switching off” the gene that is affected by the illness and so block the effects of it (Gill, 2010). That would mean that we could cure thousands of people much faster. Another way in which this discovery could help science is that scientists have been studying the dolphin’s genome for years, but with little progress because of lack of resources. But with knowing that it is so similar to our genome it would speed up research by up to 20 years! That would save up a lot of time and money.

References:


Evans, M., 2010, Human genes are helping Texas A&M veterinarians unlock the genetic code of dolphins, viewed 18th March 2012, <http://www.oar.noaa.gov/spotlite/archive/spot_texas.html>
Gill, V., 2010, Dolphins have diabetes off switch, viewed 18th March 2012, < http://news.bbc.co.uk/2/hi/8523412.stm>
Kolber, J., 2010, Dolphin DNA very close to human, viewed 18th March 2012, < http://www.articlesafari.com/2010/10/dolphin-human-dna/>
Kumar, S., 2010, Human genes closer to dolphin’s than any land animal, Discovery Channel Online, viewed 18th March 2012, < http://dsc.discovery.com/>

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