Integrative Biology Department, University of Texas at Austin, 1 University Place, Austin, TX 78712, USA.
Genes Brain Behav. 2012 Mar;11(2):222-9. doi: 10.1111/j.1601-183X.2011.00742.x. Epub 2011 Nov 23.
Genes that mediate mate preferences potentially play a key role in promoting and maintaining biological diversity. In this study, we compare mate preference behavior in two related poeciliid fishes with contrasting behavioral phenotypes and relate these behavioral differences to gene profiles in the brain. Results reveal that one poeciliid fish, the Northern swordtail, exhibits robust mate preference as compared to the Western mosquitofish, which utilizes a coercive mating system. Female swordtails display no significant difference in association time between male- and female-exposure trials, whereas female mosquitofish spend significantly less time associating with males relative to females. Furthermore, the preference strength for large males is significantly lower in female mosquitofish relative to swordtails. We then examine expression of three candidate genes previously shown to be associated with mate preference behavior in female swordtails and linked to neural plasticity in other vertebrates: neuroserpin (NS), neuroligin-3 (NLG-3) and N-methyl-d-aspartate receptor (NMDA-R). Whole brain gene expression patterns reveal that two genes (NS and NLG-3) are positively associated with mate preference behavior in female swordtails, a pattern opposing that of the mosquitofish. In mosquitofish females, these genes are downregulated when females express biases toward males yet are elevated in association with total motor activity patterns under asocial conditions, suggesting that the presence of males in mosquitofish species may inhibit expression of these genes. Both gene expression and female behavioral responses to males exhibit opposing patterns between these species, suggesting that this genetic pathway may potentially act as a substrate for the evolution of mate preference behavior.
介导配偶偏好的基因可能在促进和维持生物多样性方面发挥关键作用。在这项研究中，我们比较了两种具有不同行为表型的相关脂鲤科鱼类的配偶偏好行为，并将这些行为差异与大脑中的基因图谱相关联。结果表明，一种脂鲤科鱼类，北方剑尾鱼，表现出强烈的配偶偏好，而另一种脂鲤科鱼类，西部食蚊鱼，利用强制交配系统。与雄性暴露试验相比，雌性剑尾鱼在与雄性和雌性接触的时间上没有显著差异，而雌性食蚊鱼与雄性相比，与雌性接触的时间明显减少。此外，雌性食蚊鱼对大型雄性的偏好强度明显低于剑尾鱼。然后，我们检查了三个候选基因的表达情况，这些基因之前被证明与雌性剑尾鱼的配偶偏好行为有关，并且与其他脊椎动物的神经可塑性有关：神经丝氨酸蛋白酶（NS）、神经连接蛋白 3（NLG-3）和 N-甲基-D-天冬氨酸受体（NMDA-R）。全脑基因表达模式表明，两个基因（NS 和 NLG-3）与雌性剑尾鱼的配偶偏好行为呈正相关，这种模式与食蚊鱼的模式相反。在食蚊鱼雌性中，当雌性表现出对雄性的偏见时，这些基因下调，但在非社交条件下与总运动活动模式相关时上调，这表明雄性的存在可能抑制这些基因的表达。这两个基因的表达和雌性对雄性的行为反应在这两个物种之间表现出相反的模式，这表明这条遗传途径可能是配偶偏好行为进化的潜在基础。
