[Under the Radar]

Help us to understand, then.

If the group that carries blonde genes is not reproducing at replacement levels, how is it that the gene will not die out?

Granted, there are small populations of Caucasians who are having more than 2 children, but these groups, usually evangelical Christians, are small in number. However, other ethnic groups that do not carry blonde genes are reproducing in large numbers and doing well.

I have monitored several of these threads and seen a lot of joking and some short-tempered chastisement of those of us who "cannot pass freshmen biology." What I haven't seen is an honest analysis and description of how population genetics work, in a way that demonstrates this purported phenomenon is bogus. Please help us to understand how this allele will not die out.

[chance33_98]

So if homosexuality is genetic and they do not reproduce why do we still have them? ;)

[DBtoo]

That is so true. The blonde types have few if any children these days, whereas the darker peoples have many children. So applied math also plays into this.

[Copernicus]

What I haven't seen is an honest analysis and description of how population genetics work, in a way that demonstrates this purported phenomenon is bogus. Please help us to understand how this allele will not die out.

It's called the 3 percent rule. Nature abhors absolutes. Even if 97 percent of a population is affected by some environmental condition sufficient to cause death at least 3 percent will be resistant to that exact condition and will propagate to form a replacement population. Thus even decendants of Dinosauers still walk the earth today.

The sun could go nova tomorrow and enough terrestrial life has already escaped from Earth to eventually seed a new planet somewhere far, far away from this solar system. It would not necessarily be recognizable to the current population of Earth but it would be from and of the Earth. This would, of course, include some form of the blonde gene.

Hope this helps.

Best regards,

[WilliamWallace1999]

In genetics, an allele (alternative form of a gene) that will show in the phenotype observed characteristics of an organism) only if its partner allele on the paired chromosome is similarly recessive. Such an allele will not show if its partner is dominant, that is if the organism is heterozygous for a particular characteristic. Alleles for blue eyes in humans and for shortness in pea plants are recessive. Most mutant alleles are recessive and therefore are only rarely expressed.

For every characteristic of a plant or animal that is inherited, there are two genes present in the cells determining this characteristic in all but a few examples. By characteristic we mean height or eye colour or ability to make a particular enzyme. If the two genes are identical (homozygous state) the characteristic you see in the organism is determined by the two genes. However, one gene may be different from the other (heterozygous state). If so, the two genes are alleles contrasting genes for a characteristic. In this case it is possible that one of them determines the characteristic you see and the other does not. The characteristic you see in this case is said to be dominant. The other allele not expressed in this case will only be expressed when present in the homozygous state. This characteristic is said to be recessive.

Sometimes the allele that produces the dominant characteristic is described as being a dominant allele and the one that tends to produce the recessive characteristic as being the recessive allele. This is not really the correct use of the terms dominant and recessive. An allele is one of two or more alternative forms of a gene. This is best explained with examples. A gene which tends to produce blue eyes in a person will have an alternative allele that tends to produce brown eye colour. In a plant that may be found in tall and short forms may have an allele that tends to produce tall plants though its alternative allele produces short plants.


In real people terms, a single-gene change cannot "die-out". If a single member of a couple carries the recessive trait but is brunette, fifty percent of the kids will have the carrier state. If both members of a couple are carriers that are brunette; they will have 25% blonds, 50% brunettes that are carriers; and only 25% "pure" brunettes. The reason for the vast range of shades seen in our world is a condition called variable penetrance (stop smirking), in which the dominant gene is not able to totally shut down expression of the recessive gene.