JERUSALEM, April 10 (Xinhua) -- Researchers have found that a single genetic signal located in a part of DNA once dismissed as "junk" can determine biological sex, Bar-Ilan University said in a statement on Friday.
For decades, scientists believed that sex development depended mainly on sex chromosomes (XX or XY) and protein-coding genes. The study, published in Nature Communications, found that a tiny regulatory region called Enh13, which controls the key gene Sox9, essential for testis development, can override chromosomal sex.
Using CRISPR technology, a gene-editing tool, the researchers altered just one DNA "letter" in Enh13, triggering male development in embryos with female (XX) chromosomes and causing them to develop testes instead of ovaries.
The study highlights that so-called junk DNA, noncoding regions making up about 98 percent of human DNA, actually functions as a control system for gene expression.
Researchers said that the discovery could improve diagnosis and treatment for people with differences in sexual development, as many such cases show no mutations in the genes themselves, suggesting the answer lie in these hidden control regions. ■
