|
 
- 积分
- 17983
- 威望
- 17983
- 包包
- 26159
|

本帖最后由 细胞海洋 于 2012-8-30 12:37 编辑 & I) G" t3 ~4 Y- T, d6 {1 E3 u+ v
0 \) G7 ?+ h9 p* U8 }
) A: s4 G- V# L
Some horses — notably the harness-racing American Standardbred and the all-terrain Icelandic breed — have the ability to perform extra gaits. All horses can walk, trot, canter and gallop, but some can also ‘pace’ — moving the two legs on the same side of the body in unison — and/or perform other novel ambling gaits. A genome-wide association analysis of Icelandic horses has identified linkage between a premature stop codon in the DMRT3 gene and the ability to perform alternative gaits. Functional studies in mice show that Dmrt3 is expressed in a subset of spinal cord neurons that are crucial for the normal development of a coordinated locomotor network that controls limb movements. Dmrt3 may therefore have a key role in configuring the spinal circuits that control stride in vertebrates. In domestic horses, the DMRT3 mutation has had a major impact on the creatures’ diversification, because the altered gait characteristics of a number of breeds apparently require this mutation. Cover: A competitor in the Landsmót International Horse Competition for pure-bred Icelandic horses, Hella, Iceland, in 2004 (Arctic Images/Corbis).+ o6 I! |2 }6 x2 ^
( B2 V1 w* F# r' J1 |3 j3 h$ s" E, J
8 ~) G& D6 e& c4 n V' H' T5 M$ v2 v
[hide][/hide] |
附件: 你需要登录才可以下载或查看附件。没有帐号?注册
-
总评分: 威望 + 20
包包 + 20
查看全部评分
|