Why isn’t the Stud Mullet bald?
Personal DNA testing - whilst it is rather intriguing, is it sufficient in determining one’s traits based on genetics alone? Male baldness patterns can be linked to a complex variety of genes, but if the Stud Mullet’s genome tells him he has an 80% chance of being bald, why isn’t he bald?
It is difficult to determine the likelihood of genes affecting phenotypic traits considering the fact that many genes operate synergistically, and one gene relies on another. Genomic assessment must not only focus on the individual, but their parents and children too. There are 6 billion letters in your DNA, comprising of approximately 20,000 genes. Genes have been mapped, but how they all work together is not fully understood. Individual genes have small effects, that combined, all add up. Our environment also has an effect on baldness; if one experiences stress then the likelihood of facing hair loss is increased, known as Telogen effluvium, which can then lead to alopecia. Additionally, our phenotypic traits are a result of random chance.
What is male pattern baldness?
Baldness predominantly stems from the process of ageing - the maturation of an individual. It is also referred to as ‘androgenic alopecia,’ beginning with hair loss from the side and front of the scalp and progressively leads to the back of the head. Hair loss is a result of genes and an individual’s bodily responses to testosterone. Hair follicles start to shrink as hair follicles turn testosterone into dihydrotestosterone. Smaller hairs get thinner and eventually the hair follicle stops producing hair entirely. The baldness gene is passed down from your mother’s father. But research shows there is a link to your father’s genetics as well. Interestingly, baldness is more common amongst white men. Asian men tend to take longer to lose hair and for black males, balding is less frequent. 80% of males over the age of 70 are affected by hair loss. Whilst the remaining 20% spend their time worrying about hair loss.
Steven Pinker (age 63) has a gene which gives him double the risk of baldness, shocking because of his full head of hair; more hair than your ordinary rock star! He is the ‘stud mullet!’ As Pinker says, ‘I clearly have a 0% risk of baldness.’ So, if his genetic profile is telling him he should most likely be bald, yet he is not, then we have to question the validity of genome testing.
A study was performed on 52,000 male participants from UK Biobank to explore the genetic makeup associated with baldness. 32.6% of the sample reported no hair loss, 23% had slight hair loss, 26.9% had moderate hair loss, 18.5% had severe hair loss. That’s nearly 2/3 or the population declaring some extent of baldness. A further genomic study yielded 13,029 autosomal hits and 117 hits on the X chromosome. Males only have one X chromosome, therefore if they inherit the causative genes on that chromosome they are almost certain to express them. All of this data can tell us that an extensive amount of individual differences in baldness phenotypes can be explained by genetic variants on autosomal and X-linked chromosomes.