There are approximately 20,000 human genes. So, why do scientists study only a small part of them? | Science

Sequencing of the human genome in the 1990s was supposed to reveal all the genes that are important for health and disease. But a handful of recent studies have shown that, surprisingly, researchers still focus on only about 2,000 of the roughly 19,000 human genes encoding proteins.

Thomas Stoeger, a systems biologist at Northwestern University in Evanston, Illinois, wondered why. Now after performing a massive bioinformatic analysis reported today PLOS Biologyhe thinks he knows. Some of the reasons are obvious; others less.

Stoeger, Luís Amaral and his colleagues went through dozens of databases and other resources to compile 430 features of more than 12,000 genes, for example when a gene was discovered for the first time and the chemical and physical properties of its protein. The machine learning algorithms then worked on these data to find correlations with popularity measures, such as the number of publications on a gene and the funding provided by the National Institutes of Health. Unexpectedly, the analysis showed that a combination of only 15 genetic traits can largely predict the popularity of a gene and whether its study led to a medical drug.

Science spoke to Stoeger about why such favoritism of DNA is important and how biologists can force themselves to find hidden genomic gems. This interview has been modified for clarity and length.

Q: Why do researchers have a bias for certain genes?

A: Genes that express more protein receive more attention because they are easier to study – there is more material to analyze. Similarly, it is easier to study the genes expressed in a number of tissues of the body than in one or two places. And the genes that have a big impact when they are mutated or turned off in cells or mice are also attractive to scientists because they probably have big impacts in the body.

Q: Are there incentives for researchers to study only the most popular genes?

A: PhD Students and post-docs working on less studied genes are 50% less likely to become a group leader because they find it more difficult to obtain funding. So, in a way, they are expelled.

Q: You found that many genes that scientists do not know could be medically important. How?

A: We asked whether genes with strong evidence of a link to a disease – in large groups of people with this disease – compared to people without this disease are being studied more than other genes. We do find this trend, so that's fine. But we also find many genes related to the disease that are not well studied. This shows that it is possible to find new drugs and treatments to help people understand the biology surrounding some of these ignored genes.

Q: How can you get researchers to do this?

A: We do not know for sure. I think part of the solution will be for funding agencies to devote some of the research effort to exploring some of these less-characterized genes. Currently, we do not support researchers to do this. Adjustments would also be needed on how these researchers are supported. Maybe they need more time. Perhaps they need to create new tools because the genes they examine are more difficult to study.