Question

I'd be interested in answers about any sexually reproducing species, but for simplicity I'm going to focus on humans in this question.

If the parents are very genetically different (i.e. the number of alleles they share is much less than the average number of alleles shared by 2 people in a population), is it possible for, say, the father to be less genetically similar to his offspring than he is genetically similar to, say, his cousin? If so, what about an even more distant relative?

Of course anything is possible, so really I'm asking if it's reasonably likely and if so, how likely is it? If, for example, a genetically east Asian person and a genetically south African person had a child, would that child likely be less similar to either parent than the parents are to their respective cousins or even non-relatives from the same area?

If there are any false assumptions I'm making in the question feel free to point them out, but please provide references.

Answer 1

A child will still be more genetically similar to each parent than to more distant relatives, despite the increased genetic variance from parents of vastly different genetic backgrounds. The combination of 50% of each parent's genes ensures closer genetic resemblance between parents and offspring. Genetic diversity in offspring can be beneficial, reducing inbreeding risks and potentially increasing adaptive advantages.

Step-by-step explanation:

The concept of genetic similarity among family members is a core component of genetics and heredity. A child inherits 50% of their genetic material from each parent - half from the mother's egg and half from the father's sperm. When individuals from vastly different genetic backgrounds mate, it introduces a significant amount of genetic variance, which can lead to a lesser degree of allele sharing between the parents and offspring when compared to their relatives from the same population.

However, despite the genetic diversity originating from two genetically distinct parents, a child will still have a closer genetic resemblance to each parent than to more distant relatives like cousins or non-relatives from the same geographic region. This is due to the fact that each parent contributes exactly half of the genetic material to their child.

In cases of inbreeding, the mating of closely related individuals can lead to inbreeding depression. This is when rare, deleterious mutations come together, potentially resulting in harmful phenotypes. In contrast, when there is considerable genetic variance, such as in offspring from genetically diverse parents, there can be an adaptive advantage as it increases the chances for diverse beneficial traits and reduces the risks associated with inbreeding.