Marijuana usage may cause a significant change in the gene composition in men. According to the researchers from Duke Health a gene, associated primarily with autism, appears to undergo changes in the male gamete.
The modified gene is present in the sperms and hence can be passed on to the offspring. DNA methylation is responsible for the changes which happen inside the DNA. The process has been known to alter the activity of the DNA without changing its sequence.
The findings from the study “Cannabis use is associated with potentially heritable widespread changes in autism candidate gene DLGAP2 DNA methylation in sperm” were published in the journal Epigenetics.
A team of researchers from the Duke Health set out to find a link between cannabis use and autism. Although the findings couldn’t provide a definitive link, they were able to provide enough evidence which warrants further research on the subject.
The urgency with which the research should be pursued is perhaps increased by the ongoing legalization of marijuana use.
Marijuana is used for recreational and/or medicinal uses. But, if there is a chance that unborn people may be affected adversely, this warrants a detailed study.
This study is the first of its kind. The lead author of the study Rose Schrott conducted experiments to analyze the sperm samples of males who used marijuana. These samples were then compared against samples from men who were never exposed to marijuana.
DLGAP2, the problem gene?
Rose Schrott employed human biologics and animal modeling techniques for the analysis.
The Discs-Large Associated Protein 2 gene or DLGAP2 was the one being analyzed. DLGAP2 is known to be involved in post-traumatic stress disorder PTSD, schizophrenia, and autism among other psychotic problems.
Significant hypomethylation was identified in the sperms at DLGAP2 in people who used marijuana. As compared to controls, the hypomethylation was intense. However, according to a preexisting study smoking of marijuana increases sperm count.
Likewise, similar results were obtained when the sperm of rats exposed to tetrahydrocannabinol compared to controls. Tetrahydrocannabinol is a component found in marijuana.
The aforementioned hypomethylated state was also evident in the brains of the rats. The forebrain region of rats’ offspring bore similar traces of the hypomethylation. This suggested that the DNA in sperm has led to the passing on of the gene to the next generation.
The link between DNA methylation and gene expression
During the course of the study, a discovery was made. There existed a sex-based contrast in the relationship between DNA methylation and gene expression in human brain tissues.
High DNA methylation meant decreased gene activity. This phenomenon was found to be same across both genders.
This inverse relationship was most evident in the female test subjects and seemed to be less consistent in males. The team could not conclude as to why this happened.
This anomaly stood out as the boys with autism outnumber girls by 4:1. Furthermore, there are sex differences in the neurobehavioral symptoms.
The team is of the view that the absurd ratio between the boys and the girls may be caused by the modification in the sperm. In any case, DLGAP2 is key to understanding this as it is the gene which undergoes methylation during continued cannabis use.
While the scope of the study was vast the sample for experiments was fairly small. It constituted of 24 men, with 12 being marijuana users and other factors such as diet, sleep and exercise were avoided. This is the reason a definitive link could not be formed.
Marijuana being benign in nature is being used for medicinal purposes. But if the further studies affirm a link between its use and any deformity in the offspring the ongoing legalization would have to be checked.