A glance at the scalp of you father will give you a first indication if you'll risk baldness or not. A look at your maternal grandfather’s hair, or the lack of it, gives you an even better idea of your chances of going bald. If both men have not much hair left, you will most likely follow their example. In this blog the genetics behind the heredity of baldness will be explained, so you can make an educated guess predicting your likeliness of going bald.
The single most important cause of male pattern baldness is the genetic material someone has. This type of hair loss is hereditary and is known as androgenic alopecia. Research on identical twins has shown that male pattern baldness is mostly determined by genes. Before you read any further, note that female pattern baldness is caused by different mechanics. You can learn more about this here.
Human genes are stored on the chromosomes, which are to be found in the cell nucleus. Chromosomes are structures of coiled DNA carrying genetic information. Typically, humans have 46 chromosomes, which are grouped in pairs. 22 chromosome pairs are the autosomes. An autosome consists of one chromosome coming from the mother, and the other one stemming from the father.
The 23rd chromosome pair is different and determines your sex. The maternal chromosome is an X chromosome. During conception, a sperm cell randomly distributes another X chromosome, or a Y chromosome. Another X chromosome will result in a female (XX), while the XY combination is masculine. So, concerning males, the X chromosome is by default coming from the mother, while the Y chromosome comes certainly from the father.
The genetics of baldness
It has been demonstrated through research that the most important gene associated with baldness is the X chromosome. Since there is a fifty percent chance that this X chromosome was passed on by you maternal grandfather to your mother, the baldness of your maternal grandfather is a good predictor of your (future) baldness. The hair situation of your maternal grandmother is less clarifying, since female baldness follows a different pattern.
Besides the X chromosome there are also other chromosomes influencing baldness. There are 11 other genetic sequences of varying importance identified so far located on various chromosomes. These genes all interact which each other, affecting male pattern baldness positively or negatively. More research needs to be performed in order to fully understand the relative effect of those genes.
Why your maternal grandfather’s genes reveal more
The autosomal genes related to baldness can be inherited from either your father or mother. Since numerous autosomal genes are related to baldness, they can form pairs in many different combinations, meaning there is an unknown chance that your father’s baldness genes are effectuated. If your father or paternal grandparents are bald, you indeed have chance of becoming bald yourself, but it is unknown how probable this is.
However, since you only have one set of sex genes, the risk related to the baldness determining X-chromosome is concentrated. Therefore, you should watch your maternal grandfather’s scalp closely!