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性别决定是经典而高度保守的生物过程。在许多物种中性别决定是以遗传为基础的,个体所携带的性染色体决定了性别。然而,由于鱼类性腺发育呈现高度可变性、复杂性的特点,其性别决定机制仍未有定论。斑马鱼作为一个研究发育和疾病的重要脊椎模式动物,性别决定和分化的高度可塑性使其成为研究生理和环境因素对性腺发育影响及其作用机制的独特模型。本综述总结近年来对斑马鱼性别决定及分化过程的研究,为探索鱼类性别决定机制提供新的见解。 相似文献
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《生态学杂志》2017,(9)
性别发育是进化生物学领域备受关注的研究热点之一。性别发育主要包括性别决定和性别分化,脊椎动物的性别决定主要分为基因性别决定和环境性别决定两种模式。两栖动物的性别决定属于基因型性别决定模式,其基因型性别由受精时两性配子的性染色体决定,但性腺分化所产生的表型性别还会受环境温度和性激素的修饰。在两栖动物中性别逆转的现象普遍存在,其相关的生理和分子机制也有一定的研究。本文从性别相关基因对性别决定的影响、温度对两栖动物性别分化的影响、性激素对两栖动物性别分化的影响、温度和性激素对性别相关基因表达的影响等四方面对两栖动物性别决定和性别分化的生理和分子机制进行一定的概述,并提出了未来两栖动物性别发育研究的重点。 相似文献
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寻找人类性别决定基因的历程 总被引:1,自引:0,他引:1
动物和人类性别决定机制的探讨是生命科学中一个重要研究领域,性决定和性分化过程决定着雌性和雄性两种性别的存在。性别决定是在受精的瞬间就确定了的,是性分化的遗传基础;而性分化则是一个由早期胚胎至性成熟分化发育的复杂调控过程。该项研究不仅有益于对人类性别相关疾病的诊断治疗,而且对于动物性别的人为控制和个体性别鉴定,以及对于从低等脊椎动物到人类性别决定机制进化的探讨都具有重大价值。1 人类中存在性别决定基因对于哺乳动物的早期研究结果已使人们认识到精子有两种类型:“X精子”和“Y精子”,受精时哪种类型的精… 相似文献
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脊椎动物性别决定和分化的分子机制研究进展 总被引:8,自引:1,他引:7
哺乳类性别决定是多种转录因子和生长因子相继表达和相互调控的结果。SRY的表达启动雄性通路并诱导下游雄性特异基因SOX9、AMH等的表达。FOXL2在雌性未分化性腺表达,WNT-4和DAX1也在雌性性别决定或分化时期表达,表明雌性通路也是受特定基因调控的,而并非“默认通路”。鸟类的性别也是由遗传基因决定的,EFT1(雌性)和DMRT1(雄性)可能是性别决定候选基因。爬行类为温度性别决定的典型,温度可能通过调节雌激素水平和控制性别特异遗传基因表达决定性别。大部分两栖类性别受环境因素影响,但发现DMRT1和DAX1可能与其精巢发育有关。鱼类性别决定和分化方式差异很大,多种因素(遗传基因、环境因素、类固醇激素等)参与了这一过程。从青Q鳉Y染色体定位克隆的DMY,被认为是第一个非哺乳类脊椎动物雄性性别决定基因。所有这些表明脊椎动物性别决定和分化机制是多样化的。 相似文献
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U. Liberman 《Journal of mathematical biology》1991,29(7):653-669
The two basic one locus sex determination models, diploid individual sex determination and parental sex determination, are generalized to the multilocus framework. As in the single locus case, it is established that there are two classes of polymorphic equilibria, equilibria with even sex ratio and equilibria with equal allele frequencies in the two sexes. The condition for external stability of this second class equilibria to invasion by a new mutant allele is that a new appropriately averaged sex ratio near the equilibrium be moved closer to the even sex ratio. However, stable polymorphisms with noneven sex ratio are not those that have a sex ratio as close as possible to 1/2, in contrast to the single locus case.Research supported in part by NIH grants GM 28016 and GM 10452 and a grant from the U.S.-Israel Binational Science Foundation 相似文献
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黑斑蛙的减数分裂研究 总被引:1,自引:0,他引:1
本文研究了黑斑蛙的减数分裂,发现其性染色体所形成的性二价体主要呈末端与末端联接,浓缩期占79.6%,中期Ⅰ占75%,这进一步证明黑斑蛙确实存在XY型性别决定机制,这种XY型性染色体虽形态相同,但已发生了质的分化,可能是同型异质。黑斑蛙的性染色体并不形成性泡,少数二价体有中间交叉。 相似文献
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The release rate of the pheromone component Z-7-dodecenyl acetate was determined for individual female Trichoplusia ni by using small glass tubes filled with Porapak Q to extract pheromone from air in the immediate vicinity of the everted gland. The change in release rate as a function of time was determined by taking sequential 5 min. samples from individual 4-day-old females through each pheromone release period over an entire night. The release rate was found to decline exponentially from a mean of 22 ng per min. initially to 12 ng per min. at the end of 20 min., the average length of a pheromone release period. Pheromone collections were also made from females of different ages, using a single tube of Porapak per female to collect pheromone for an entire night. The nightly mean release rate increased significantly with age, although the time spent releasing pheromone per night decreased significantly with age (to 6 days old). 相似文献
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The aim of the present review, which highlights some relationships between sex hormones, the CNS and pain, is to provide reference points for discussion on one of the most intriguing aspects of pain pathophysiology: the presence of sex differences in the response threshold to phasic painful stimuli and in the incidence of chronic pain syndromes. The first part of the review deals with sex steroids and their mechanisms of action. In the second part, the connections between sex steroids, the CNS and pain are illustrated to introduce possible areas of discussion in the study of sex differences in experimental and clinical pain. 相似文献
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鱼类性别决定和分化机制极为复杂,通过性腺组织切片鉴定得出黄河鲤从未分化性腺发育为Ⅱ期精巢、卵巢的时间为受精后第40天到第80天。选取一些可能参与黄河鲤性别决定分化相关的基因(amh、ar、cyp19a、cyp19b、dax1、dmrt1、er、foxl2、nobox、sox9a、sox9b、zp2)进行实时荧光定量PCR分析各个基因在受精后40d、45d、50d、55d、65d和80d的表达情况。结果显示性别决定相关基因在50d都有高表达,推测45-50 d为性别决定的关键时间。ar、amh、dax1、dmrt1、sox9a、sox9b六个基因在80d雄性表达量升高,且雄性明显高于雌性,推测这些基因参与精巢分化发育过程。cyp19a、cyp19b、foxl2、nobox、zp2五个基因在80d雌性表达升高,且高于雄性,推测其可能参与卵巢分化发育。 相似文献
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温度对江黄颡鱼性分化的影响 总被引:8,自引:0,他引:8
通过组织学方法观察江黄颡鱼原始生殖细胞(PGCs)迁移、生殖嵴生成和性腺分化,并且探讨在不同温度培育下性腺分化的差异。实验结果显示:1日龄仔鱼PGCs位于鱼体中肠背方的脏壁中胚层中;5日龄时,PGCs迁移到背方的腹膜上皮;8日龄时,生殖嵴形成;14日龄时,原始性腺形成;23日龄时,性腺开始分化。从孵化后的第10天开始,分别用(20±0.5)、(24±1.0自然水温、对照组)、(30±0.5)和(34±0.5)℃4种水温培育仔鱼达25天。实验结束后统计结果显示:对照组和(20±0.5)℃组的雌、雄性比接近1∶1(分别为1∶1.09和1.22∶1);(30±0.5)℃组的为1∶4.89,雄性率达(83.3±0.7)%;(34±0.5)℃组的为2.85∶1,雄性率仅为(26.4±0.4)%。提示(30±0.5)℃可使幼鱼性腺发育趋向雄性,(34±0.5)℃则使幼鱼性腺发育趋向雌性。实验结果表明,江黄颡鱼的性分化是属于温度依赖型性别决定。 相似文献
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芦笋性别决定与性别分化研究进展 总被引:1,自引:0,他引:1
从芦笋性别表现及其决定的遗传基础、性别分化途径,性别决定基因的定位以及性别分化特异表达基因的分离与分析等方面来综述芦笋性别决定与性别分化最新研究进展。目前,已构建了围绕芦笋性别决定基因M比较精细的遗传图谱,将M定位在L5染色体着丝点附近的0.63 cM区域内,并构建了含有8个跨叠克隆群的物理图谱,但由于大量重复序列的存在,跨叠克隆之间的空隙不能闭合;同时先后分离得到11个芦笋花器官发育特异表达基因,并通过序列分析和原位杂交等技术对这些基因的功能进行了分析。最后,对今后进一步研究提出了建议。 相似文献
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First results from two strategies aimed at elucidating the genetics of sex in the dioecious genus Actinidia Lindl. (Actinidiaceae) support the hypothesis that sex-determining genes are localized in a pair of chromosomes which, although
cytologically indistinguishable, function like an XX/XY system with male heterogamety. A. chinensis Planch., a close relative of the kiwifruit [A. deliciosa (A. Chev.) CF Liang et AR Ferguson], has diploid and tetraploid races. Bulk segregant analysis to find sex-linked markers
revealed two markers whose inheritance patterns in three diploid families showed X and Y linkage and indicated that the male
is the heterogametic sex. Some recombination between the markers and the sex-determining loci was also demonstrated. Sex ratios
in 12 progenies from controlled crosses varied around 1:1, as expected for an XX/XY system.
Received: 20 December 1995 / Revision accepted: 24 April 1997 相似文献