Before this study, by using different methods scientists could analyze the entire genome of a person and say that an individual has more or fewer copies of a particular gene, but not the absolute number of copies. For example, scientists have known that some people have an increased copy-number of a gene that confer some resistance to HIV, but couldn't tell how many.
The UW researchers further examined the much-studied genomes from three healthy individuals: a European (DNA research pioneer James D. Watson), a Yoruban African individual from Nigeria, and a Han Chinese. The researchers were able to predict copy-number differences among the individuals, even when there were many copies, such as 5 in one person compared to 12 in another. The researchers conservatively validated 113 genes that were copy-number variable among the three people, but more genes are suspected to be copy-number variable. Several of the validated gene differences are known to be of biomedical relevance. They include, for example, genes related to eye and skin diseases, and many others that play a role in the immune system. The researchers noted that several human genes with the most variable copy numbers correspond to a torrent of segmental duplications that occurred within the common ancestor of apes and humans.
In talking about their study, the researchers mentioned that next-generation technology for sequencing the human genome has far greater detection power and costs substantially less than the traditional sequencing method known as Sanger sequencing. The new technologies are beginning to distinguish subtle dissimilarities between nearly identical gene copies.
"This can provide researchers with a more accurate assessment of specific gene content and insight into functional constraints," Alkan explained.
"The newer, faster genome sequencing platforms," Alkan added, "ma
|Contact: Leila Gray|
University of Washington