Ethnicity could be a major factor determining how our immune system works, according to a new study.

Researchers have discovered that genes controlling antibodies, how well they operate and even what illnesses they are able to fight off can actually vary from person to person based on their ethnicity.

A team of 14 North American scientists have completely sequenced the human genome's complex immunoglobulin heavy-chain locus, a key producer of antibody-encoding genes used to fend off infections. The researchers said the link between antibody makeup and ethnicity surfaced when they screened the chromosomes of 425 people of Asian, African and European descent for several DNA insertions and deletions.

"Time will confirm the extent to which this is true. But we've found that sections of the IGH-chain locus' DNA sequence are either missing or inserted into a person's genome, and this could vary depending on ethnicity," researcher Corey Watson said in a press release.

Key to unlocking the discovery was the team's success at determining the sequence of a highly-repetitive DNA chain, one million nucleotides long. A nucleotide is a minute part of the DNA chain. This research could advance understanding of variations among individuals in terms of their ability to fight off viruses such as influenza or HIV.

The findings could mean that drugs, treatments and vaccinations could have a different effect on each patient. The researchers say the finding could be the beginnings of creating treatments that could be tailor-made for each individual patient.

"These findings could mean that past environmental exposures to certain pathogens caused DNA insertions or deletions in different ethnic groups, which could impact disease risk," Watson said.

The American Journal of Human Genetics published its findings in the article Complete Haplotype Sequence of the Human Immunoglobulin Heavy-Chain Variable, Diversity and Joining Genes and Characterization of the Allelic and Copy-Number Variation, in its March 28 issue.