近日，韩国的科学家发现，在胚胎期敲除雌性小鼠的一个单基因，可使雌性小鼠变成“同性恋”。

这个简易的手术使得基因被敲除的雌性小鼠拒绝雄性小鼠的求爱行为，同时试图与其雌性同类进行交配。研究者发现，敲除FucM基因（该基因影响了雌激素的水平，进而使大脑受到影响）使得雌性小鼠在长大过程中的行为与雄性接近。

韩国科学技术院的帕克教授（Chankyu  Park）领导了这项研究。他说：“基因被改造的雌性小鼠的大脑发展轨迹被改变，使其在性取向方面接近雄性同类。”其实，全球科学家在寻找“同性恋与基因”之间的关联已有相当长的时间，但是进行这项最新研究的学者强调称，目前该试验这还无法表明是否与人类的性活动存在某种相关性。

通过敲除这种特殊基因，科学家认为他们可以通过阻止雌性小鼠大脑过滤掉性激素，使雌性小鼠受到额外雌激素影响。虽然雌激素（的变化）能使雌性小鼠的大脑雄性化，但是在人类中并未发现相同的效应。

帕克教授接下来将考察该基因产生的酶（一种海藻糖变旋酶）是否对人类性活动具有影响，不过他承认想找到愿意参与实验的自愿者可能“十分困难”。他的大部分研究都已经发表在《英国医学委员会遗传学》。

原文出处：

BMC Genetics. PMID: 20609214 

Male-like sexual behavior of female mouse lacking fucose mutarotase.
Park D, Choi D, Lee J, Lim DS, Park C.

ABSTRACT: BACKGROUND: Mutarotases are recently characterized family of enzymes that are involved in the anomeric conversions of monosaccharides. The mammalian fucose mutarotase (FucM) was reported in cultured cells to facilitate fucose utilization and incorporation into protein by glycosylation. However, the role of this enzyme in animal has not been elucidated. RESULTS: We generated a mutant mouse specifically lacking the fucose mutarotase (FucM) gene. The FucM knockout mice displayed an abnormal sexual receptivity with a drastic reduction in lordosis score, although the animals were fertile due to a rare and forced intromission by a typical male. We examined the anteroventral periventricular nucleus (AVPv) of the preoptic region in brain and found that the mutant females showed a reduction in tyrosine hydoxylase positive neurons compared to that of a normal female. Furthermore, the mutant females exhibited a masculine behavior, such as mounting to a normal female partner as well as showing a preference to female urine. We found a reduction of fucosylated serum alpha-fetoprotein (AFP) in a mutant embryo relative to that of a wild-type embryo.

CONCLUSIONS: The observation that FucM-/- female mouse exhibits a phenotypic similarity to a wild-type male in terms of its sexual behavior appears to be due to the neurodevelopmental changes in preoptic area of mutant brain resembling a wild-type male. Since the previous studies indicate that AFP plays a role in titrating estradiol that are required to consolidate sexual preference of female mice, we speculate that the reduced level of AFP in FucM-/- mouse, presumably resulting from the reduced fucosylation, is responsible for the male-like sexual behavior observed in the FucM knock-out mouse.