Talk:Przewalski's Horse
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[edit] interbreeding with other equids
The article states that experts are not in agreement as to whether domestic horses and Przewalski's Horse are really separate species. But the two species differ in how many chromosomes they possess. Domestic horses have 64 chromosomes, while Przewalski's Horse have 66. The article states that domestic horses and Przewalski's Horse are the only two equids that can interbreed. The article on the horse says that the reason why donkeys and horses can't interbreed is that they differ in the number of chromosomes they have. Donkeys only have 62. So, then, why aren't the cross between a domestic horse and a P's horse sterile?
- Because a different species is not defined by it's number of chromosomes alone. Maybe this quote from Status and Action Plan for the Przewalski’s Horse (Equus ferus przewalskii) by Simon Wakefield, John Knowles, Waltraut Zimmermann and Machteld van Dierendonck will help you understand:
- "Although Przewalski’s horse can hybridise with domestic horses to produce fertile offspring (Ryder et al. 1978; Trommerhausen-Smith et al. 1979), the existence of 2n=66 chromosomes in Przewalski’s horse identifies it as being more different from its domestic relatives (2n=64) than are any two breeds of domestic horse (Ryder 1994). They also show a number of other consistent differences in their appearance: the manes of Przewalski’s horses are erect with no forelock, and the upper part of the tail has short guard hairs, unlike domestic horses, which have long, falling manes and long guard hairs all over the tail; a dark dorsal stripe runs from the mane down the back and dorsal side of the tail to the tail tuft; three to ten dark stripes can be present on the carpus and, generally, the tarsus (Groves 1994). Przewalski horses, contrary to domestic horses, shed their tail and mane hair once per year.
- Other studies of the genetic differences between Przewalski’s and domestic horses have indicated very little genetic distinction between them. Only four alleles at four separate serological marker loci have been identified as specific to Przewalski’s horse (Bowling and Ryder 1987), the vast majority of blood protein variants are present in both Przewalski’s and domestic horses and even the fastest evolving DNA region known in mammals (the mitochondrial DNA control region), does not show significant differences between the two types of horse (Ishida et al. 1995; Oakenfull and Ryder 1998). Thus it is clear that Przewalski’s and domestic horses are very closely related and have in the past interbred, but the fixed chromosomal number difference between them indicates that they are distinct populations (Oakenfull et al. 2000)." So they are not two seperate species, but belong to the same one! Pmaas 11:06, 16 February 2006 (UTC)
- And another possible helpfull quote from Ishida, N., Oyunsuren, T., Mashima, S., Mukoyama, H., and Saitou, N. J Mol Evol. 1995. Mitochondrial DNA sequences of various species of the genus Equus with special reference to the phylogenetic relationship between Przewalskii's wild horse and domestic horse. Journal of molecular evolution; 41(2): 180–188. [1]:
- "The noncoding region between tRNAPro and the large conserved sequence block is the most variable region in the mammalian mitochondrial DNA D-loop region. This variable region (ca. 270 bp) of four species of Equus, including Mongolian and Japanese native domestic horses as well as Przewalskii's (or Mongolian) wild horse, were sequenced. These data were compared with our recently published Thoroughbred horse mitochondrial DNA sequences. The evolutionary rate of this region among the four species of Equus was estimated to be 2-4 x 10(-8) per site per year. Phylogenetic trees of Equus species demonstrate that Przewalskii's wild horse is within the genetic variation among the domestic horse. This suggests that the chromosome number change (probably increase) of the Przewalskii's wild horse occurred rather recently." Pmaas 11:41, 16 February 2006 (UTC)
"The Przewalski horse has 66 chromosomes, while the domestic horse has 64. The Przewalski horse can be crossed successfully with the domestic horse, producing offspring with 65 chromosomes. Unlike the offspring of a domestic horse and an animal such as a donkey or zebra, the offspring of a Przewalski/domestic horse is not sterile and can be crossed back to either species. If the offspring is crossed back to a domestic horse, the resulting animal will have 64 chromosomes and very few Przewalski characteristics."
65 chromosome horses cannot breed with other 65 chromosome horses. I've included this information in the article with a reference. HeWasCalledYClept (talk) 19:25, 6 June 2008 (UTC)
[edit] Did I read that right?
I think that the articles says that the UK Forestry Commission hopes the horses will help recreate scenes from the Iron Age? What does the pronoun reference? Please make that a lttle clearer to eliminate ambiguity.
hey thats great
- I've found the reference! Pmaas 08:03, 27 May 2006 (UTC)
- Forestry Commission. 2004. FC Wales turns clock back thousands of years with 'wild' solution to looking after ancient forest site. News release, No: 7001, 16 September 2004. [2]
- how about putting in that as a footnote in the main article? Or I can... !Montanabw 04:15, 28 June 2006 (UTC)
[edit] size
I came here looking for their size. What am I supposed to do with a value for their length when horses are usually measured by their shoulder height? Any way to convert this? dab (ᛏ) 16:13, 14 June 2006 (UTC)
They are 12 to 13 hands, I put in a reference. However, the stallion at the National Zoo in Washington, DC, looked bigger, closer to 14 hands. Maybe just soft living! Montanabw 04:13, 28 June 2006 (UTC)
[edit] Numbers
According to Prague Zoo who maintains the studbook of Przewalski's horse there were 1860 horses of which less than 300 were living freely. [3] The studbook contains records of 4650 horses since 1899. The 1,500 numbers in the article are those in zoos (e.g. 1495 in 2002).
There's also second area, Tachin Tal in the Gobi national park, where the horses are reintroduced (somehow less sucessful than the Hustai Nuuu). Pavel Vozenilek 11:21, 21 October 2006 (UTC)
[edit] removed section
I removed the section "Interesting Facts". The section had been marked with {{citation needed}} since 25 June 2006. Michael Slone (talk) 05:00, 5 January 2007 (UTC)
- No disagreement here, looks like vandalism, actually. I'm surprised none of us got around to tossing it earlier. Thanks. Montanabw 18:17, 5 January 2007 (UTC)
