生活在圣誕島（位于爪哇島南部印度洋東部的一座島嶼）上的紅螃蟹在度過了幾個月悠閑的時光后，便會開始一場漫長的馬拉松比賽,。
在5到6天的時間里,，這些螃蟹會從它們位于雨林的家中遷徙到海里進行交配，其全程約為5公里,。
那么它們究竟是如何在這么短的時間里變得如此敏捷呢,？為了找到問題的答案，研究人員來到圣誕島上,，并在紅螃蟹的遷徙期以及6個月后——這時它們會不慌不忙地返回雨林——采集了它們的腿部肌肉,。
通過對這兩種樣本進行遺傳學分析，研究人員發(fā)現(xiàn)兩者在14種基因的表達上存在巨大差異,。通過改變自身產(chǎn)生能量的方式,，這些變化幫助紅螃蟹的腿部肌肉為漫長而艱巨的旅程作好準備,。
在那些不需要長途跋涉的紅螃蟹中,，基因活動使得肌肉纖維能夠從事于無氧代謝——這種模式不需要氧的參與并適合于短期運動。另一方面,，在那些遷徙去海邊的紅螃蟹中,，基因的表達促進了有氧代謝——這種模式需要氧的參與并最適合于高耐力運動。研究人員表示,，為了應付比賽,，迄今為止，人類依然不得不通過大運動量的訓練來提高成績,。
研究人員在5月號的《實驗生物學雜志》網(wǎng)絡版上報告了這一研究成果,。（生 物 谷Bioon.com）
生物谷推薦原文出處：
Journal of Experimental Biology doi: 10.1242/jeb.033829 This Article
Migration-related changes in gene expression in leg muscle of the Christmas Island red crab Gecarcoidea natalis: seasonal preparation for long-distance walking
Ute Postel, Fiona Thompson, Gary Barker, Mark Viney* and Steve Morris
School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK
During their annual breeding migration the Christmas Island land crab Gecarcoidea natalis sustains locomotion aerobically for up to 12 h per day compared with just 10 min during the dry season when their muscles quickly become anaerobic. A seasonal transition to an endurance-muscle phenotype would thus seem essential for migrating crabs. The current study employed a gene discovery approach comparing two expressed sequence tag (EST) libraries, one each for leg muscle from dry (non-migrating) and wet season (migrating) crabs. The 14 most abundant transcripts differed in their representation between the two libraries. The abundances of transcripts of genes predicted to code for different proteins forming contractile muscle components, including actin, troponin and tropomyosin, were significantly different between seasons and thus between physiological states. The shift in the isoform composition of the contractile elements provided evidence for a switch from slow phasic (S1) to slow tonic (S2) fatigue-resistant muscle fibres. A tropomyosin (tm) transcript aligned with a tm isoform of lobster (tmS2), and semi-quantitative RT-PCR confirmed this isoform to be more abundant in the migrating crab muscle. Two LIM protein coding genes, a paxillin-like transcript (pax) and a muscle LIM protein (mlp), were relatively up-regulated in muscle of wet season crabs. These proteins have a fundamental role in muscle development and reconstruction, and their comparative up-regulation is consistent with a remodelling of leg muscle for migration in the wet season. Such a transition would result in an increased representation of aerobic endurance-type fibres concomitant with the greater aerobic exercise capacity of the migrating red crabs.
