Reproductive isolation from a cross between a horse and a donkey or between a mare and a donkey, respectively. These animals are nearly always sterile due to the difference in the number of chromosomes between the two parent species. Both horses and donkeys belong to the genus "Equus", but "Equus caballus" has 64 chromosomes, while "Equus asinus" only has 62. A cross will produce offspring (mule or hinny) with 63 chromosomes, that will not form pairs, which means that they do not divide in a balanced manner during meiosis. In the wild, the horses and donkeys ignore each other and do not
Titus Sextius Africanus Titus Sextius Africanus Titus Sextius Africanus was a Roman senator who was deterred by Agrippina the Younger from marrying Junia Silana. He served as a suffect consul in 59 AD. In 62 AD, he took the census in the provinces of Gaul, together with Quintus Volusius Saturninus and Marcus Trebellius Maximus. Saturninus and Africanus were rivals, and both hated Trebellius, who took advantage of their rivalry to get the better of them. His name occurs in a fragment of the Fratres Arvales. Titus Sextius Cornelius Africanus, who served as a consul with Trajan in 112 AD, was related to Africanus.