Top 10 genetics facts

A female. This kind of coat coloring, which combines two colors other than white (black and red in this case), is known as tortoiseshell, and it is found almost exclusively in female cats. This is because the X chromosome determines the color of the cat, and there are no color genes in Y chromosome. Thus, female cats with XX chromosomes may be three colored (including white), while male cats with XY chromosomes cannot. (with the exception of very rare XXY sterile males).

Africans. Interbreeding between Neanderthals with modern humans took place several times. Neanderthal-derived DNA was found in the genome of contemporary populations in Europe and Asia, it accounts for 1–4% of modern genomes. Neanderthal genes are absent from most modern populations in sub-Saharan Africa.

Genetic disorders. Since almost all Amish descend from about 200 18th-century founders, genetic disorders that come out due to inbreeding increase the mortality rate among Amish children. In contrast, cancer rates are 56 percent of the national rate.

Men. It is much less likely for a woman to be red-green colorblind than a man, since this common type of color blindness is caused by a recessive gene in the X chromosome. For a woman, both of her X chromosomes would have to be affected. A man only has one X chromosome, so he is more likely to be color-blind.

63. A mule is the offspring of a male donkey and a female horse. Mules have 63 chromosomes, a mixture of the horse's 64 and the donkey's 62.

174. The cultivated kiwi fruit, Actinidia deliciosa, is a hexaploid species with a total number of 174 chromosomes. Many of cultivated plants are polyploids created by selective breeding, and are usually unable to interbreed with their diploid ancestors.

Manx. The Manx taillessness gene is dominant; kittens from two Manx parents are generally born without any tail. However, having two copies of the gene is lethal in utero, so breeders avoid breeding two entirely tailless Manx cats together. Typically, when bred with non-Manx cat, tail length is random throughout a litter of kittens.

Chimpanzees and humans share a common ancestor about four to six million years ago. The genetic similarity is so high, that the two species of chimpanzees, Pan troglodytes and Pan paniscus, have been proposed to belong with H. sapiens in the genus Homo, rather than in Pan.

The The distance between chromosome positions. In genetics, a centimorgan (abbreviated cM) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01. It is often used to infer distance along a chromosome. However, It is not a true physical distance.

Progeria is an extremely rare genetic disorder in which symptoms resembling aspects of aging are manifested at a very early age. Those born with progeria typically live to their mid-teens to early twenties. It is a genetic condition that occurs as a new mutation, and is rarely inherited as carriers usually do not live to reproduce.