If blue eyes are regressive (overridden by brown eyes) then, how could millions of north Europeans end up with blue eyes, supposing that blue eyes come from a single mutation?
In: Biology
Just because it’s not the dominant gene doesn’t mean it can’t be a common gene.
The gene for dwarfism is the dominant gene, but it’s not very common because it’s not beneficial to survival and two copies of that gene is fatal.
Polydactylism (extra fingers) is also a dominant gene, but the gene hasn’t been around long enough to be common in humans, but it has in cats, which is why polydactyl cats are a fairly common sight.
All that being the recessive gene means is that you need two copies of it to express it. Since blue eyes aren’t harmful in any way, once the gene for it entered the gene pool, it stuck around until eventually it was common enough that people could get two copies.
Latest Answers