CSCG - Close Species Comparative Genomics
[Comparative Genomics]
Definition
In one sentence, comparative genomics is comparison of completely sequenced genomes of various species. Through sequencing many kinds of genomes ranging from human to mouse to yeast, it can be figured out what kinds of organisms are more developed in specific environment. It also made it possible to understand more about functions of human genome, and develop more advanced medical systems to cure human disease.
The most important point of comparative genomics is that, by comparing common characteristics of two organisms, the evolutionarily conserved DNA sequence can be found out. Thus, it is start with aligning genomic sequences and analyzing orthologous sequences.
Principle
The core idea of the field of comparative genomics is that, like mentioned above, sequence, which is conserved over millions of times in distant species, implies an important biological function, and it could have been constrained by leaving several nucleotides among its own motif. It means that the conservation is not always meaning that whole base should be remained in DNA. In DNA, exons are generally well conserved between distant species in a very accurate form, thus it is easy to make a gene models. Conversely, the elements which have roles in regulation are hard to model. In that sense, the comparative genomics is very efficient. By comparing human, mouse, rat, and dog genomes, thousands of noncoding elements are analyzed which would be never possible without it.
Examples of Result
1. A study discovered that about 60 percent of genes are conserved between fruit flies and humans, meaning that the two organisms appear to share a core set of genes. Two-thirds of human genes known to be involved in cancer have counterparts in the fruit fly.
2. A comparative genomics analysis of six species of yeast prompted scientists to significantly revise their initial catalog of yeast genes and to predict a new set of functional elements that play a role in regulating genome activity, not just in yeast but across many species.
3. Researchers studying milk production have mapped genes that increase the yield of high-fat milk in cows, resulting in higher production levels and potentially a significant economic impact. This is one of many studies aimed at increasing food production.
4. Scientists have found genes that increase muscling in cattle by twofold; they found the same genes in racing dogs, and such results may foster human performance studies.
5. Comparisons of nearly 50 bird species' genomes revealed a gene network that underlies singing in birds and that may have an important role in human speech and language. The bird researchers also found gene networks responsible for traits such as feathers and beaks.
6. In recent years, researchers in the National Human Genome Research Institute (NHGRI) intramural program also have studied the genomics of various cancer types in dogs, including common cancers and other diseases, to try to develop new insights into the human form of the condition. In some cases, they have mapped genes contributing to these disorders.
7. In other studies, NHGRI researchers are comparing how genes affect body shape and size in dogs to better understand growth and development. Studies of dogs with sleep problems have revealed genes and pathways - and potential drug targets - to treat sleep problems.
Reference
1. https://en.wikipedia.org/wiki/Comparative_genomics
