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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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高等植物的性别表型具多态性,这与植物性别决定的遗传基础有关,高等植的性别与性别决定基因,性染色体及常染色体有关,其性别决定系统有性别决定基因决定性别、性染色体决定性别及X染色体与常染色体间的基因平衡决定性别等多种方式。 相似文献
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环境决定爬行动物性别研究的进展 总被引:4,自引:0,他引:4
爬行动物的性别决定机制有两种,一种是由环境决定性别,另一种是异型性染色体决定性别。前者,在爬行动物中具有普遍性;未发现有异型性染色体的爬行动物,其性别由环境因子决定。剧烈的环境条件,可能压倒基因型性别决定。H-Y抗原,可检测未发现异型性染色体决定性别物种的遗传决定型。 相似文献
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昆虫性别决定机制存在多样性和复杂性,其中膜翅目昆虫的性别决定由单双倍体决定,单倍体为雄性,二倍体为雌性。本文就膜翅目昆虫的性别决定模式和分子机制进行综述。膜翅目昆虫性别决定有6种模式,即互补性性别决定(complementary sex determination, CSD)、多位点互补性性别决定(multiple-locus CSD, ml-CSD)、基因组印记、母体效应、内共生体诱导产雌单性生殖、父本遗传基因组消除(paternal genome elimination, PGE)。其中,CSD机制是目前在膜翅目昆虫中普遍接受的性别决定模式。而蜜蜂的CSD性别决定机制是膜翅目昆虫性别决定模式中的典型代表,受csd→fem→dsx这一调控级联的控制。 相似文献
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哺乳动物性别决定和性反转 总被引:13,自引:0,他引:13
目前已知SRY仅是涉及性别决定过程的基因之一.近年来又发现和克隆了许多可能参与性腺分化与发育的基因,如副中肾抑制基因MIS,也称抗副中肾激素基因AMH;SRY相关基因SOX9;编码甾类因子的基因SFI;X-连锁的DAX基因;Wilm′s肿瘤抑制基因WTI;以及X-连锁的剂量敏感基因DSS等,并新建立了性别决定的Z-基因模型,DSS-基因模型和Jimenez等的模型,较合理地解释了哺乳动物性别决定的分子机理和以前难以解释的各种奇特的性反转现象,使性别决定的研究取得了长足的进展,但仍有一些悬而未决的问题有待于进一步探索. 相似文献
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Sex Determination by Sex Chromosomes in Dioecious Plants 总被引:5,自引:0,他引:5
Abstract: Sex chromosomes have been reported in several dioecious plants. The most general system of sex determination with sex chromosomes is the XY system, in which males are the heterogametic sex and females are homogametic. Genetic systems in sex determination are divided into two classes including an X chromosome counting system and an active Y chromosome system. Dioecious plants have unisexual flowers, which have stamens or pistils. The development of unisexual flowers is caused by the suppression of opposite sex primordia. The expression of floral organ identity genes is different between male and female flower primordia. However, these floral organ identity genes show no evidence of sex chromosome linkage. The Y chromosome of Rumex acetosa contains Y chromosome-specific repetitive sequences, whereas the Y chromosome of Silene latifolia has not accumulated chromosome-specific repetitive sequences. The different degree of Y chromosome degeneration may reflect on evolutionary time since the origination of dioecy. The Y chromosome of S. latifolia functions in suppression of female development and initiation and completion of anther development. Analyses of mutants suggested that female suppressor and stamen promoter genes are localized on the Y chromosome. Recently, some sex chromosome-linked genes were isolated from flower buds of S. latifolia. 相似文献
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《Current biology : CB》2020,30(20):R1256-R1258
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LANG JEFFREY W.; ANDREWS HARRY; WHITAKER ROMULUS 《Integrative and comparative biology》1989,29(3):935-952
Incubation temperature determines sex in the mugger crocodile,Crocodylus palustris. Exclusively females are produced at constanttemperatures of 28.0°C through 31°C. At 32.5°C,only males are produced. Both sexes are produced in varyingproportions at 31.5, 32.0, and 33.0°C. Embryo survival isnot affected within this range, but developmental rate and totalincubation time are strongly temperature dependent. In naturalnests laid in breeding enclosures, cool incubation temperaturesproduced only females whereas males were produced only in warmnests. Clutch sex ratios were female or male biased. Yearlysex ratios (=percent male) varied from 0.05 to 0.58; overallsex ratio during six nesting seasons was 0.24 (1 male: 3 females).Sex ratio and incubation time vary with nest location and temperaturein a manner consistent with the constant temperature results.Incubation time decreases with increasing incubation temperature,and is an accurate predictor of sex ratio in the field and laboratory. To date, temperature-dependent sex determination (TSD) has beenreported in five species of Crocodylus and in three speciesof Alligatorinae; but the TSD patterns in these groups differ.The TSD pattern of C. palustris is similar to that of C. porosus.Nesting in C. palustris is synchronized with the seasonal availabilityof thermal regimes suitable for incubation. Resultant sex ratiosare a consequence of when and where eggs are laid. Early nestsare located in warm, sunny sites; in contrast, late season nestsare located in the shade. An egg transplant experiment demonstratedthat sex ratios could be altered by simple manipulations ofnest temperatures in the field. The adaptive significance ofTSD in crocodilians may relate to the influence of incubationtemperature on various hatchling attributes, particularly growth. 相似文献
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Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so much variation in the amount and precision with which they adjust their offspring sex ratios? 相似文献
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