中新网昆明1月28日电(顾一航)记者28日从中科院昆明动物研究所获悉，该所科学家通过理论模型研究发现，资源变化、环境选择压力等因素将导致一个物种出现不同的性别比例。对于人类来说，环境选择压力的增大将会导致其后代雌性比例的增大。

Beijing kunming January and report(The a air)Reporter and the Chinese academy of sciences, from kunming institute of animal,This study found that scientists through the theoretical model,Resources change/Environmental factors such as selection pressure will lead to a species appear different gender ratio.For humans,Environment selection pressure increases will lead to the increase of the proportion of the female offspring.

　　自然界的大多数物种的性比都是1:1，然而少数物种在进化过程出现偏雌或偏雄的性别比例。

The nature of most species of sex ratio is 1:1,However, a few species in the evolutionary process in partial female or partial male gender ratio.

　　1930年发表的著名的Fisher定理认为，性别的进化就是两性合子随机结合的过程，其后代出现雄性或雌性的几率就像随机投掷硬币所出现正、反两面一样，完全是一个随机的过程。

Published in 1930 famous Fisher theorem think,The evolution of sex is amphoteric zygote random combination of the process,Their offspring appear male or female chance as random throwing COINS are in/Back two sides,Completely is a random process.

　　上世纪60年代开始的基因遗传频率选择理论和资源分配理论认为，近亲交配、局域交配竞争或环境选择压力将会导致种群偏雌性性别比例。

The 1960 s genetic frequency selection theory and resource allocation theory is that,inbreeding/Local mating competition or environmental selection pressure will lead to population partial female gender ratio.

　　但这些理论仍然难以解释相同环境下为何有些物种出现偏雌性比，而有些物种却是偏雄性的性别比例；以及为何同一物种在不同的年龄阶段、环境条件会出现不同的性别比例。究竟什么机制或原因决定、影响一个物种的性别比例一直是学术界未曾有效解决的科学问题。

But these theories are still hard to explain the same environment why some species than the females in partial,And some species are partial male gender ratio;And why the same species in different age stages/Environmental conditions will appear different gender ratio.What mechanism or causes decisions/Influence a species of sex ratio was the research have not effectively solve the scientific questions.

　　中国科学院昆明动物研究所研究员王瑞武和云南大学数学系教授李耀堂、博士研究生王亚强等合作，将经济学中的弹性理论引入进化生物学。其理论模型发现生态学著名“多生少管选择”和“优生优育选择”，其本质就是资源变化对幼崽存活率影响大小(即资源的存活弹性系数)不同所致。

The Chinese academy of sciences researcher at the institute of animal WangRuiWu kunming and yunnan university mathematics professor LiYaoTang/Doctoral students WangYaJiang cooperation, etc,The economics of elastic theory in evolutionary biology.The theoretical model found famous ecology"ShaoGuan have more choice"and"Eugenic and superior nurture choice",Its essence is the resources change on cub survival effect size(That is the survival of the elastic coefficient of the resources)Caused by different.

　　模型同时发现资源的存活弹性系数与环境选择压力将同时影响性别比例的演化，性比的改变可能是由于个体的激素或荷尔蒙水平的变化所致。

Model also found resources live elasticity coefficient and environmental selection pressure will also influence the evolution of the gender ratio,Sex ratio changes may be due to individual hormone or hormone level changes caused by.

　　研究结果表明，对选择的优生优育繁殖策略的个体或物种而言，如老虎、人类等，环境选择压力的增大将会导致其后代雌性比例的增大；而对选择多生少管这样粗放式繁殖策略的个体或物种而言，如老鼠、蚊子等多数昆虫，环境选择压力的增大将会导致其后代雄性比例的增大；如果资源变化对幼崽存活率影响不大或没影响(非弹性区间)，环境选择压力的增大，将不会改变其后代的性别比例。

The results of the study show that,To choose reproductive strategy of eugenic and superior nurture individual or species,Such as the tiger/Human beings,Environment selection pressure increases will lead to the increase of the proportion of the female offspring;But to choose to have more ShaoGuan such extensive breeding strategy of individual or species,Such as mice/Most insects such as mosquitoes,Environment selection pressure increases will lead to the increase of the proportion of the male offspring;If resources change on cub survival or did not affect the impact is not big(Inelastic interval),Environment selection pressure increases,Will not change their offspring gender ratio.

　　研究人员介绍，该理论模型有效解释为何有些物种出现偏雌性比，而有些物种却是偏雄性的性别比例。对同一物种而言，其不同的年龄阶段或环境条件下资源的存活弹性系数都不一样，其性别比例也将因年龄阶段的不同或环境条件的差异而发生改变，该模型因而也解释了包括人类在内的很多物种在局部范围内出现的性别失调现象。

The researchers said,The theory model is effective explain why some species than the females in partial,And some species are partial male gender ratio.To the same species,The different age stages or environmental conditions of the resources live elastic coefficient is different,The gender ratio will be different age differences or environmental conditions change,The model and also explains including humans, many species in the local scope of gender imbalance phenomenon appears.