AP BIOLOGY

Detailed explanation-1: -How are freckles passed on? Freckles are associated with a variant of a gene called MC1R. MC1R alerts the body when exposed to harmful UV radiation is taking place. This is a dominant gene, meaning anyone with at least one copy of the freckle variant from either parent will have freckles.

Detailed explanation-2: -Freckling is a recessive trait, so both parents have to be carriers and pass the tendency on for it to show up, says Amit Sharma, M.D., a dermatologist at the Mayo Clinic, who researches dermatologic genetics. The so-called gene for freckling is actually a benign mutation of the MC1R gene, which regulates pigment.

Detailed explanation-3: -The presence of freckles is related to rare alleles of the MC1R gene, though it does not differentiate whether an individual will have freckles if they have one or even two copies of this gene. Also, individuals with no copies of the MC1R do sometimes display freckles.

Detailed explanation-4: -Freckles tend to run in families. People (especially kids) who have fair complexions are most likely to freckle.