Mixed twins

Mixed twins are fraternal twins born to multiracial families which differ in skin color and other traits considered to be racial features.

From a biological point of view, the differences in these fraternal or dizygotic twins from two biracial parents are not surprising. In humans, a relatively small number of genes are thought to be responsible for human skin color. Different alleles or gene variants code for differences in the melanin found within the skin. Within some groups we find high frequencies of dark skin alleles, while others have high frequencies of light skin alleles, for example. The parents of such twins, who are typically both of mixed race, have a combination of alleles for light and dark skin in their genome.

Each sperm or egg cell will possess a random selection of genes from their mother or father. While not the most probable event, a sperm or egg may randomly acquire, for example, mostly alleles that confer light skin coloration or mostly alleles that confer dark skin coloration. In such cases we may find non-identical twins where twins differ from each other quite dramatically in terms of skin color or other physical characteristics.

There have been numerous sets of mixed twins.^{[1][2][3][4][5]}

See also

• Heteropaternal superfecundation, when the twins have different fathers

References

1. ^ Black and white twins are one in a million
2. ^ EXCLUSIVE: EBONY AND IVORY
3. ^ Twins in Black and White
4. ^ ANOTHER PAIR OF BLACK & WHITE TWINS
5. ^ The world's least alike twins

• Daily Mail, February 21, 2006: "Black and White Twins"
• ABC's Good Morning America: "One Twin's White, The Other's Black"