The humanzee (sometimes chuman, manpanzee or chumanzee) is a hypothetical hybrid of chimpanzee and human, thus a form of human–animal hybrid. Serious attempts to create such a hybrid were made by Soviet biologist Ilya Ivanovich Ivanov in the 1920s, and possibly by researchers in China in the 1960s, though neither succeeded. The portmanteau humanzee for a human–chimpanzee hybrid appears to have entered usage in the 1980s. Feasibility The possibility of hybrids between humans and other apes has been entertained since at least the medieval period; Saint Peter Damian (11th century) claimed to have been told of the offspring of a human woman who had mated with an ape, and so did Antonio Zucchelli, an Italian Franciscan capuchin friar who was a missionary in Africa from 1698 to 1702, and Sir Edward Coke in "The Institutes of the Lawes of England". Chimpanzees and humans are closely related, sharing 95% of their DNA sequence and 99% of coding DNA sequences. Hybridization between chimpanzees and bonobos has been documented, and they share 99.6% of their genomes. However, genetic similarity, and thus the chances of successful hybridization, is not always correlated with visual appearances. For example, pugs and huskies look quite dissimilar, but belong to the same species and subspecies and can hybridize freely. On the other hand, rabbits and hares look very similar, but are only distantly related and cannot hybridize. All great apes have similar genetic structure. Humans have one pair fewer chromosomes than other apes, with ape chromosomes 2 and 4 fused in the human genome into a large chromosome (which contains remnants of the centromere and telomeres of the ancestral 2 and 4). Chromosomes 6, 13, 19, 21, 22, and X are structurally the same in all great apes. Chromosomes 3, 11, 14, 15, 18, and 20 match between gorillas, chimpanzees, and humans. Chimpanzees and humans match on 1, 2p, 2q, 5, 7–10, 12, 16, and Y as well. Some older references include Y as a match between gorillas, chimpanzees, and humans, but chimpanzees, bonobos, and humans have recently been found to share a large transposition from chromosome 1 to Y not found in other apes. The degree of chromosomal similarity among apes is roughly equivalent to that found in equines. Interfertility of horses and donkeys is common, although sterility of the offspring (mules) is nearly universal (with only around 60 exceptions recorded in equine history). Similar complexities and prevalent