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Topic: Sex determination system

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Talk:Sex-determination system - Wikipedia, the free encyclopedia From the definition, one could conclude that a sex-determination system is a method that, when applied to a certain individual, tells you whether that individual is a male or a female. In that sense, a sex-determination system for dogs would be "look if you can find testicles". I have read information to the effect that the WW:WZ system for birds AND snakes, (i'm not sure about insects) is a reverse xy system in that as the articles says two of the same chromosomes are needed for male determination, instead of the XX style in human. www.wikipedia.org /wiki/Talk:Sex-determination_system   (312 words)

Sex determination in Hymenoptera Regardless of such homologies, it seems clear that the sex determination systems of the Hymenoptera reflect in many ways the peculiar life histories and conditions of individual species. Skinner, S.W. and Werren, J.H. The genetics of sex determination in Nasonia vitripennis (Hymenoptera: Pteromalidae). A second peculiarity in Hymenopteran sex determination is the existence, in at least one species, of a so-called selfish chromosome which is inherited at greater than Mendelian proportion. www.sccs.swarthmore.edu /users/99/mahowald/hymenoptera.html   (4726 words)

XY sex-determination system - Wikipedia, the free encyclopedia The XY sex determination system was first described independently by Dr. Nettie Stevens and Edmund Beecher Wilson in 1905. In the XY sex-determination system, females have two of the same kind of sex chromosome (XX), while males have two distinct sex chromosomes (XY). The XY sex-determination system is a well-known sex-determination system. en.wikipedia.org /wiki/XY_sex-determination_system   (264 words)

SWA3Sex.doc Many other organisms have environmental sex determination (ESD). Sex in these species is determined by fertilization: fertilized eggs develop into diploid females, and unfertilized eggs develop into haploid males. In many species of fish and reptiles, the sex of developing embryos is determined by the temperature at which those embryos develop. webpub.alleg.edu /dept/bio/bio340/SWA/SWA3Sex.doc   (519 words)

Sex Determination Martin, J. Interrelation of inversion systems in the midge Chironomus intertinctus (Diptera: Nematocera) I. A sex-linked inversion. It seems likely that the sex determination pathway will be related to that of Drosophila melanogaster subsequent to the action of the sexlethal gene, which does not appear to be involved in sex determination in other groups of Diptera (Martin & Lee 1999). 'jacksoni' has lead to the creation of a new sex chromosome - but not a change in MD site. www.genetics.unimelb.edu.au /Martin2/sexdt.html   (690 words)

RNA and sex determination in Caenorhabditis elegans: Post-transcriptional regulation of the sex-determining tra-2 and fem-3 mRNAs in the Caenorhabditis elegans hermaphrodite -- Puoti et al. 2 (10): 899 -- EMBO Reports Sokol, S.B. and Kuwabara, P.E. (2000) Proteolysis in Caenorhabditis elegans sex determination: cleavage of TRA-2 by TRA-3. RNA and sex determination in Caenorhabditis elegans: Post-transcriptional regulation of the sex-determining tra-2 and fem-3 mRNAs in the Caenorhabditis elegans hermaphrodite -- Puoti et al. Kuwabara, P.E. and Kimble, J. (1992) Sex determination in Caenorhabditis elegans. emboreports.npgjournals.com /cgi/content/full/2/10/899   (3648 words)

EVOLUTIONARY BIOLOGY: ON CHROMOSOMES AND SEX DETERMINATION There is an even wider range of sexual systems in teleost fishes, with examples of self-fertilizing hermaphrodites [2], sequential hermaphrodites [3], and environmental sex determination [1]. Even within tetrapod vertebrates, however, there is a wide diversity of sex determination mechanisms, with many examples of species with genetic sex determination but microscopically similar X and Y chromosomes, and numerous cases of environmental sex determination [1]. Sex, according to the traditional explanation, allows simultaneous improvements at several genetic loci, whereas multiple adaptations must occur sequentially in clonal organisms. scienceweek.com /2004/sc041112-3.htm   (1024 words)

Sex Determination Sex determination and sex linkage in water frogs... Evolution of the genetic cascade that regulates sex determination in insects... The Role of Estrogen in Turtle Sex Determination and the Effect of PCBs... www.scienceoxygen.com /biology/360.html   (304 words)

Work: Sex Sex in butterflies is done just like sex in birds, but fruit flies are like us. Imagine, however, some other, more complex system that produces reasonable equilibrium frequencies so long as the frequencies of each type stay within a narrow range, but wanders off into never-never-land if there is heavy predation on one type. Both are completely backwards from the system used by the magpie squawking outside our window, and the sphinx moth getting ready to pop out of the pupal case we're keeping on our windowsill. www.alumni.caltech.edu /~copeland/work/fish.html   (1691 words)

Sox3 Is Required for Gonadal Function, but Not Sex Determination, in Males and Females -- Weiss et al. 23 (22): 8084 -- Molecular and Cellular Biology Campomelic dysplasia and autosomal sex reversal caused by mutations in an SRY-related gene. from hypoplasia to XY sex reversal (11), and the absence of Expression of Sox3 throughout the developing central nervous system is dependent on the combined action of discrete, evolutionarily conserved regulatory elements. mcb.asm.org /cgi/content/full/23/22/8084   (5095 words)

Eulimnadia Staring at this last equation for a while indicates that (1) the sex ratio is generally not even, (2) the sex ratio is always biased towards females unless males are much more fit than females. Sex in Eulimnadia is determined by a gene or gene region as follows: Interestingly, the sex ratio varies from pool to pool, with males ranging from 0-35%. www.zoology.ubc.ca /~otto/Talks/Shrimp/Talk.html   (614 words)

RNA Binding Protein Sex-Lethal (Sxl) and Control of Drosophila Sex Determination and Dosage Compensation -- Penalva and Sánchez 67 (3): 343 -- Microbiology and Molecular Biology Reviews The WT1 gene is implicated in mammalian sex determination, and The Drosophila sex determination gene snf is utilized for the establishment of the female-specific splicing pattern of Sex-lethal. that affect the sex determination process without affecting mmbr.asm.org /cgi/content/full/67/3/343   (8999 words)

Minna Heikkilä. Development of the adreno-genital system. ISBN 951-42-6844-X After sex determination Wnt-4 was downregulated in the testis, but the expression persisted until birth in the ovary. Although the genetic sex of an embryo is determined at conception by the presence or absence of the Y chromosome, both females and males have bipotential, undifferentiated gonads early in their development. Wnt-4-deficient female mice demonstrated a partial female-to-male sex reversal and a reduction in the number of oocytes, while the Müllerian duct was absent from both sexes. herkules.oulu.fi /isbn951426844X   (289 words)

PAG-XI-P662: SEX CHROMOSOME MARKERS IN PACIFIC SALMON (Oncorhynchus spp.) Pacific salmon possess an XY sex determination system where the two sex chromsomes are still largely homologous and heteromorphic structure in the vicinity of the sex-determination locus (the differential region) is difficult to identify cytogenetically. In family crosses, the markers were found by PCR analysis to be tightly linked to the sex-determination locus (SEX) on the Y chromosome. Despite their close linkage with SEX in the four species examined, neither of the two markers are sex-linked in sockeye salmon, rainbow trout or Atlantic salmon indicating that this linkage was established after the early radiation of the Pacific salmon. www.intl-pag.org /pag/11/abstracts/P5o_P662_XI.html   (278 words)

Infectious Sex However, in several wild populations, this system is overridden by cytoplasmic sex factors produced by endocytic bacteria. In the woodlouse Armadillium vugare (a terrestrial isopod), sex determination in some populations is determined by a symbiotic bacterium. In most populations, sex determination is characterized by female heterogamy (ZW) and male homogamety (ZZ). zygote.swarthmore.edu /sex9.html   (198 words)

X chromosome - Wikipedia, the free encyclopedia Chromosomal conditions involving the sex chromosomes often affect sex determination (whether a person has the sexual characteristics of a male or a female), sexual development, and the ability to have children (fertility). The sex chromosomes are one of the 23 pairs of human chromosomes. The X chromosome is one of the two sex chromosomes in humans and other animals (the other is the Y chromosome). en.wikipedia.org /wiki/X_chromosome   (1068 words)

Encyclopedia: X The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. The MPAA film rating system is a system used in the United States and instituted by the Motion Picture Association of America to rate a movie based on its content. Semiotics - also known as semiology - is the study of signs, both individually and grouped in sign systems, and includes the study of how meaning is transmitted and understood. www.nationmaster.com /encyclopedia/X   (6962 words)

Sex-determination system - Hutchinson encyclopedia article about Sex-determination system Most fish have a very flexible system of sex determination, which can be affected by external factors. In humans, sex is determined by the male. In many species, the sex of an individual is dictated by the two sex chromosomes (X and Y) it receives from its parents. encyclopedia.farlex.com /Sex-determination+system   (277 words)

Sex-determination system - Wikipedia, the free encyclopedia In the WZ sex-determination system, the situation is reversed: females have two different kinds of chromosomes (WZ), and males have two of the same kind of chromosomes (ZZ). A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. The WZ sex-determination system is found in birds and some insects and other organisms. www.wikipedia.org /wiki/Gonosome   (277 words)

Upto11.net - Wikipedia Article for W WZ denotes female in the WZ sex-determination system. In the Metric system, W is the symbol for the watt, the SI derived unit for power. W is the name of a graphical windowing system for Unix platforms; see W Window System. www.upto11.net /generic_wiki.php?q=w   (277 words)

Conservation of the global sex determination gene tra-1 in distantly related nematodes -- Pires-daSilva and Sommer 18 (10): 1198 -- Genes and Development Marin, I. and Baker, B.S. The evolutionary dynamics of sex determination. Schedl, T., Graham, P.L., Barton, M.K., and Kimble, J. Analysis of the role of tra-1 in germline sex determination in the nematode Caenorhabditis elegans. Hediger, M., Burghardt, G., Burghardt, G., Siegenthaler, C., Buser, N., Hilfiker-Kleiner, D., Dubendorfer, A., and Bopp, D. Sex determination in Drosophila melanogaster and Musca domestica converges at the level of the terminal regulator doublesex. www.genesdev.org /cgi/content/full/18/10/1198   (5300 words)

Inbreeding and Sex Determination Even though haplo-diploidy may mitigate some of the costs of inbreeding, many hymenopterans have a complementary sex determination (CSD) system that functions poorly when inbreeding occurs. Because insects in the order Hymenoptera have a haplo-diploid genetic system, with diploid females arising from fertilized eggs, and normal haploid males developing form unfertilized eggs, harmful recessive alleles will be expressed frequently and selected against in males. To a first approximation, this prediction seems to true; many closely inbred chalcid wasps do not have CSD, and many bees and hunting wasps known to have CSD are sexually active only after they have left their natal area where they would be most likely to encounter relatives. homepages.wmich.edu /~cowan/research/HymBreedSexDet.html   (524 words)

A novel regulatory mutation in the C. elegans sex determination gene tra-2 defines a candidate ligand/receptor interaction site -- Kuwabara 122 (7): 2089 -- Development Exploring the Envelope: Systematic Alteration in the Sex-Determination System of the Nematode Caenorhabditis elegans Sex determination in the nematode C. elegans is dependent on cell-to-cell A novel regulatory mutation in the C. elegans sex determination gene tra-2 defines a candidate ligand/receptor interaction site dev.biologists.org /cgi/content/abstract/122/7/2089   (390 words)

Sex Determination Waterbury, J.A., Horabin, J.I. Bopp, D. and Schedl, P. (2000) Sex determination in the Drosophila germline is dictated by the sexual identity of the surrounding soma. Bopp, D., Calhoun, G., Horabin, J.I., Samuels, M.E., and Schedl, P. Sex-specific control of Sex-lethal is a conserved mechanism for sex determination in the genus Drosophila. [home] [people] [research] [chromatin] [sex determination] [orb] [Germline] [molbio homepage] www.molbio.princeton.edu /labs/schedl/Sex_determination_page.htm   (802 words)

Exploring the Envelope: Systematic Alteration in the Sex-Determination System of the Nematode Caenorhabditis elegans -- Hodgkin 162 (2): 767 -- Genetics , J., 1986  Sex determination in the nematode Caenorhabditis elegans: analysis of tra-3 suppressors and characterization of fem genes. Maternal sex determination by the autosomal gene tra-3: or sex determination in response to nutritional conditions, www.genetics.org /cgi/content/full/162/2/767   (7245 words)

(WO 01/52726) CLASSIFICATION SYSTEM FOR SEX DETERMINATION AND TISSUE CHARACTERIZATION The method of sex determination provides additional information about primary sources of systematic tissue variability, namely, the thickness of the dermis and the subcutaneous fat. Categorization of subjects on the basis of the determination is therefore suitable for further spectral analysis and the measurement of biological and chemical compounds, such as blood analytes. (57) Instrumentation and procedures for noninvasively determining the sex of human and animal subjects in vivo have been developed based on the irradiation of skin tissue with near infrared light. www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/52726.010726   (195 words)

Student's Study Guide for Lesson Twelve : Sex Determination, Chromosomes and Mosaicism A Punnett square for sex determination using the sex chromosomes. Among the sex chromosomes, men have XY and women have XX. There is no difference among the sexes because each individual is both sexes. www.synapses.co.uk /genetics/ssg12.html   (1104 words)

Human Anatomy Chapter 27 -- Evolution Atlas Sex chromosomes are common in reptiles where either male or female can be the heterozygous sex, but sex chromosomes are often absent in amphibians and fish. Humans (and all mammals) possess sex chromosomes, X and Y. Females are homogametic (i.e., homozygous for X: XX) and males are heterogametic (i.e., heterozygous: XY). The main functions of the reproductive system are to 1) reproduce, and 2) produce genetically diverse offspring. cwx.prenhall.com /bookbind/pubbooks/martini10/chapter27/custom2/deluxe-content.html   (1104 words)

present projects Primary sex determination in Megaselia scalaris is effected by the presence or absence of an epistatic Maleness ( M) gene. The zebrafish, Danio rerio, has environmental or polygenic sex determination (not clear yet which) and, hence, no sex chromosomes were found. Traut W (1999) The evolution of sex chromosomes in insects: differentiation of sex chromosomes in flies and moths. www.bioweb.mu-luebeck.de /RESEARCH/CHROMOSO/ChromStru.html   (1104 words)

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