According to a new study performed by the scientists at the Center for Cellular and Molecular Biology (CCMB) and Indian Institute of Chemical Technology (IICT), Hyderabad, partial deletion of the heterochromatin region of the Y chromosome may exhibit to the increased stress vulnerability and reduced new neuron formation in mice.
The Y-chromosome in mammals is the male sex determining chromosome. In the developing embryo it is responsible for specifying male body parts and restores the sperm supply in adults. As per recent studies Y-chromosome plays an important role in determining the characteristic aggressive behavior of male mice. The function of most Y-linked genes in the brain is not known much, while many genes on the Y-chromosome are expressed in both the testes and the brain.
The lead author for the molecular aspects of the study Rachel Jesudasan, emeritus scientist, CCMB, told that researchers initially thought that the heterochromatin region of the Y-chromosome is not functional.
Her team was studying the factors involved with infertility by using mutant mice with deletions in heterochromatin region of the Y-chromosome. Surprisingly, they observed certain behavioral alterations, in addition to sperm-related defects. Jesudasan said that they were keen on understanding the neural mechanism and behavioral pattern involved with this activity.
Based on this researchers conducted a series of experiments to evaluate anxiety and depression-like behaviors in the mice with partial deletions in the Y-chromosome. They found that the mice reacted more strongly to an acute stressor and showed increased anxiety-like behaviors after being forced to swim in water for 10 minutes.
It could have been because of the impaired formation of new neurons in the hippocampus, a brain region that is involved in the regulation of mood, learning and memory. The researchers observed changes in the expression of several genes which mediate the process of neurogenesis.
Sumana Chakravarty, Principal scientist at IICT, Hyderabad who is also a lead author for the behavioral aspects of the study told that the behavioral changes observed can be due to the altered neurogenesis in its hippocampus region that make them more susceptible to depression.
William Davies, senior lecturer at Cardiff University at Wales said that the study results are interesting and suggest a potential new mechanism conferring protection against affective conditions in males, he was not involved with the study, but cautioning, however, that the effect sizes in the study are small and the results need to be replicated in larger experimental unit before any firm conclusion.
By: Aishwarya Sharma