Comparative genomics
Now that we have a map of the human genome, we have to learn how to read it and figure out which gene does what.
Of the estimated 30,000 genes in the human genome, we have very little idea about what each one does. One way of studying genes is to directly compare the entire genome with other organisms. This is called comparative genomics.
The human genome is extremely complicated. By comparing it with the genomes of other species, such as mice or fruit flies, we gain insights into the similarities and differences and can learn more about the function of human genes.
The organisms scientists are using in comparative genomics are known as model organisms. That is, they provide a model against which the human genome can be studied. It doesn't matter that we have two legs and mice have four, or that we have opposable thumbs and mice have claws. On a DNA level, humans and other organisms aren't that different. On average, the DNA sequence of mouse and human genes is 85% similar.
Since 1995, the genomes of more than 180 organisms have been sequenced. These include chimpanzee, mouse, rat, pufferfish, fruit fly, sea squirt, roundworm, baker's yeast, the bacterium Escherichia coli, kangaroo, honey bee, dog and chicken.
In 2008, the platypus genome was sequenced by Australian and American researchers. Analysis of the genome showed genetic similar ities to reptiles, fish and birds, giving clues to the evolutionary origins of this egg-laying mammal.
For updated information on completed genomes:
http://www.genomenewsnetwork.org
Wallaby genome project
Australia is adding to the global genome research effort by sequencing the genome of the tammar wallaby (Macropus eugenii), an Australian marsupial.
Australian Genome Research Facility / DPI Victoria
Why the wallaby? To find out important genes that make us human, we compare our genome with that of other animals. Mammals such as the mouse are too similar, while animals such as chickens are too different. Marsupials such as the tammar wallaby are perfectly in between.
Marsupials are particularly valuable ‘alternative mammals’ for comparative studies. They have a number of unique features that can help scientists better understand the mechanisms controlling fertility, seasonal breeding, pregnancy and lactation in all mammals.
Sequencing the wallaby genome has the potential to provide benefits in human medicine and agriculture. Benefits will also come from applying genome-scale information to conservation, ecology and pest management in a variety of marsupial species.
For more information on the Wallaby Genome Project, go to:
http://www.agrf.org.au/news-item-2.html
http://kangaroo.genomics.org.au/public/