What is the potential role of the male Y chromosome and alcoholism? Would this make sense that males are twice as likely to become alcoholics than females?
The Role of the Y Chromosome in Alcoholism
The possibility of a link between the Y chromosome and alcoholism has been interesting researchers for many years. It is a well known fact that men have a higher rate of developing alcoholism than women. The most obvious difference in men and women is their combination of sex genes present when conceived. To be considered male on the genotypic level, or genetic level, a male has both an X and a Y gene whereas women have two X genes. Imbedded in the Y chromosome is a region called SRY, or sex-determining region Y, which when inherited with the Y chromosome, fetuses become male. Researchers think that an "alcoholism gene" might exist in some families and could be passed down via the SRY on the Y chromosome. With this information it seemed that this link between men and alcoholism would be found in the Y chromosome.
Alcoholism, just like any psychiatric disorder, can be inherited through the generations in a family; this further supports that alcoholism must have some sort of genetic component. There is even support that an extra inherited Y chromosome in a male, so he would have an X and two Y's would give rise to alcoholism in men. As finding men with this disorder and asking to graph their chromosomes in a karotype is an ordeal, most scientists have only speculated.
Family and Social Impact
However genetics is not the only way to become an alcoholic. Society and family behaviors can cause the onset itself. Men growing up with the disorder constantly around them can become an alcoholic without the necessary Y chromosome component. Also men living in an environment that portrays men as stronger and tougher when drinking will likely increase the need to drink with that individual.
What about women? It has been found that men who have two X chromosomes develop male because of a transfer between the SRY region and a portion of the X chromosome. This crossover turned a potential female into an otherwise functional male. Scientists believe that this can occur in the opposite; women inheriting the "alcoholic" region onto one of their X chromosomes and becoming genetically induced alcoholics.
As with most genetic and psychiatric disorders not one single mutation or alteration in the genetic make-up in someone can cause the disorder. Instead researchers are finding that it is a combination of many genes, called heterogeneity that can influence other genes to cause a mutation or alteration, and the environment. The odds of becoming an alcoholic where alcoholism runs in the family and in the genetic code can be very high, but this also depends on other factors. Just because a person is immersed in alcoholism does not mean that they are automatically set on the same path; but can do the very opposite. The person might not ever touch a drink, or refuse to put themselves in a situation with alcohol. It depends on the environment and the genetic make-up of the individual.
- PNAS. Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits - http://www.pnas.org/content/96/7/4204.abstract
- Forensic Science International. The human Y chromosome: function, evolution and disease - http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T6W-42SXF3V-G&_user=427436&_coverDate=05%2F15%2F2001&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1448831609&_rerunOrigin=google&_acct=C000020480&_version=1&_urlVersion=0&_userid=427436&md5=45314dd021b85a454c376206486f3fb8&searchtype=a