Comparative Placentation
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چکیده
The ancestry of horses from five-toed species via the small Eohippus of the American continent has been a prime topic of study for evolutionary biologists. It is best traced in two contributions: by Simpson (1951), and by Thenius & Hofer (1960). Coming from the American continent, the equid ancestors distributed to Eurasia while speciating into the extant members during their expansion to the West and into Africa. In the process, chromosomal fusions occurred in the equidae, causing karyotypes to evolve that range from 66 to 32 chromosomes, whilst preserving the same amount of DNA. The current domestic horse is thought to have derived from the Mongolian wild horse, Equus przewalskii. Other authors, however, have considered the extinct Tarpan to be the ancestral species of the domestic horses. A very large number of different horse breeds have been produced during their domestication, ranging from large tract animals to very small ponies.
منابع مشابه
IFPA Meeting 2011 workshop report III: Placental immunology; epigenetic and microRNA-dependent gene regulation; comparative placentation; trophoblast differentiation; stem cells.
Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.
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