Throughout history man has searched for the cause of hair loss. It is only in recent years, with greater knowledge of genetics and the chemistry of sexual hormones, that we have begun to understand the causes. One thing that we do know for certain: no matter what we eat, what our lifestyles may be, or what kind of vitamins we take, we never grow more hair follicles than we were born with.
Predominant type
The most common type of baldness is called Male Pattern Baldness or more scientifically, Androgenetic Alopecia. In Androgenetic Alopecia, hair follicles that are producing healthy, terminal hairs begin to produce thinner, shorter, more brittle hairs with weaker shafts (this process is called Miniaturization and the hairs involved are called Miniaturized hairs). Eventually, these follicles produce only fine, almost invisible, short, vellus hairs, or they may die out altogether.
Finding the Genes
Common baldness cannot occur without the presence of specific inherited genes. These genes can be passed on by either parent. A gene is a single bit of chemically encoded hereditary instruction that is located on a chromosome and actually represents a tiny segment of DNA.
Predominant type
The most common type of baldness is called Male Pattern Baldness or more scientifically, Androgenetic Alopecia. In Androgenetic Alopecia, hair follicles that are producing healthy, terminal hairs begin to produce thinner, shorter, more brittle hairs with weaker shafts (this process is called Miniaturization and the hairs involved are called Miniaturized hairs). Eventually, these follicles produce only fine, almost invisible, short, vellus hairs, or they may die out altogether.
Finding the Genes
Common baldness cannot occur without the presence of specific inherited genes. These genes can be passed on by either parent. A gene is a single bit of chemically encoded hereditary instruction that is located on a chromosome and actually represents a tiny segment of DNA.
Chromosomes occur in pairs (humans have 23 pairs), and every individual gets one set of chromosomes from each parent. The genetics of androgenetic alopecia is complicated and hair loss is now felt to involve more than one gene. When several genes govern a trait, it is called polygenic. Genes that are located on the X or Y-chromosomes are call sex-linked.
Genes on the other 22 pairs of chromosomes are called autosomal. It is felt that the genes governing common baldness are autosomal. This means that the baldness trait can be inherited from the mother's side of the family or the father's side. The commonly held notion that baldness comes only from the mother's side of the family is incorrect, although for reasons not fully understood, the predisposition inherited from an affected mother is of slightly greater importance than that inherited from an affected father.
The genes involved in androgenetic alopecia are felt to be dominant. Just because a person has the genes for baldness, doesn't mean the trait will manifest itself. The ability of a gene to affect one's characteristics, i.e. be visible in a particular individual, is called "expressivity".
The genes involved in androgenetic alopecia are felt to be dominant. Just because a person has the genes for baldness, doesn't mean the trait will manifest itself. The ability of a gene to affect one's characteristics, i.e. be visible in a particular individual, is called "expressivity".
Studying the Factors
Gene expression is related to a number of factors, the major ones being hormones and age, although stress and other factors can play a role. To put it simply, a man whose father and uncles are severely bald may have minimal hair loss himself, either because the baldness genes have not been passed on or because the expression of the baldness gene that he did inherit is limited. It is of interest that, to date, none of the genes for male pattern baldness have been identified.So lot opportunities are there in this field that result in genetic engineering to prevent common baldness.
