A baby's hair color is sometimes the average of both parents' hair color, with preference toward the parent with the darker hair, according to Parents magazine. However, there are many alleles in both parents' DNA that contribute to a baby's hair color, states Indiana University.Continue Reading
The common belief is that genetic inheritance is determined by only two alleles — that the dominant gene beats out a recessive one. However, this is not true when it comes to determining hair color, according to Indiana University.
A person’s hair color is determined by the amount of eumelanin, or dark brown pigment, and pheomelanin, reddish pigment in his DNA, notes John H. McDonald of the University of Delaware. The combination of these pigments and the amount of each determine a person’s exact shade of hair color.
In terms of hair color, when a baby whose genetic inheritance involves a combination of dominant and recessive alleles, his hair color is one out of many different possibilities, concludes Indiana University. In general, dark hair shows genetic dominance over light hair; however, there are many alleles that contribute to a person’s hair color inheritance.
Parents who have similar hair color may have a baby whose hair is within the same color range, notes Parents magazine. However, a child sometimes expresses the recessive genes of his parents. For example, a parent who carries a recessive gene for blond hair but has dark hair could potentially have a child with blond hair, explains Parents.
One change in a DNA base pair can alter drastically a person’s traits and his gene expression, according to Harvard University genetics professor Hopi Hoekstra, as cited by National Geographic. Blond hair, specifically, can be linked to a single letter mutation in the genetic code.Learn more about Biology