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February 21, 2024

Ethnicity may determine immunity

By TONY WU | May 9, 2013

Various aspects of human beings are determined by genetics. However, there is always the nature versus nurture debate. Recently, a team of researchers led by Corey Watson, a postdoctoral at the Mount Sinai School of Medicine, discovered important links between immunity and genes. There is substantial evidence that the nature side of the debate is more influential than nurture — at least in terms of the immune system.

Immune systems vary from person to person. There are people who have substantial defense against common germs and viruses and just never seem to catch a cold or flu. On the other hand, there are people with weak immune systems who succumb to virtually every sickness circulating around the community. In the recent discovery, Watson and his team attempted to find the correlation between various genes coded by the DNA and their effect on the immune system.

Watson states, “Antibodies are essential components of the immune system and … the genes in our genome that encode antibodies remain only partly described at the genetic level.”

The first step of the study is to completely sequence the DNA of various subjects. This provides a detailed genetic map of each subject and allows scientists to conduct comparisons. In comparing the various parts of the DNA, scientists uncovered something interesting: ethnicity is an important factor in how the immune system operates. Across multiple subjects, scientists found that there is a chain of nucleotides that are either missing or inserted according to the subject’s ethnicity.

The chain of nucleotides is referred to as the IGH-chain locus, which is shorthand for immunoglobulin heavy chain locus. Just as the name suggests, this chain of nucleotides is responsible for the genetic code for more than 50 different types of antibodies within the immune system. These antibodies are then used by the B cells in the immune system to combat sicknesses and infections.

The experiment extracted a single chromosome from a subject and sequences the IGH-chain locus for that particular individual. The data is then used to conduct comparisons for the 11 common differences within that particular sequence. The researchers then identified eleven significant insertions and deletions of genetic coding for antibodies within that sequence.  

By obtaining multiple samples, scientists were able to attribute the difference to the subject’s ethnicity. Across 425 subjects encompassing Europeans, Asians and Africans, the experimenters discovered that individuals can possess between five to eleven copies of IGH genes.

The study is currently in its early stages, but it shows significant promise in gaining a deeper understanding of the human immune system. While the effects of the deletion and insertion of genes in the IGH chain is not clear, the significant differences across different ethnicities points to an area of immunity research that has been neglected. These differences across different groups point to the possibility that each group will react differently to drugs designed for the entire population. Since these individualized responses are not taken into consideration in present drug development processes, the effectiveness of new drugs may be reduced and may produce unforeseen effects for different populations.

Watson discusses his vision for the research, “We hope to use the sequence data generated during this study to inform better descriptions of these genes at the DNA level … applying this information to understanding how genetic variation in antibody genes impacts on antibody production in humans.”


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