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Topic: Z chromosome

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	Genitics1
		The only exception is the sex chromosome pair known as Z and W. All male pigeons will have two Z chromosomes and every hen a combination of one Z and one W. We know that the Z chromosome carries many different gene locus points while a W Chromosome doesn't seem to have any genes.
		W and Z. The W is very small and only found on a hen along with one Z while a cock has two Zs making up his sex chromosome pair and both Z's will be large with a large number of assigned genes.
		When the female is the homogametic member the symbol X is used for her large sex chromosome or X//X set while Z is used when it is the male that carries the two large sex chromosomes or Z//Z set.
	www.angelfire.com /ga/huntleyloft/Genetics1.html (3243 words)

	Y chromosome - Wikipedia, the free encyclopedia
		Other organisms have mirror image sex chromosomes: the female is "XY" and the male is "XX", but by convention biologists call a "female Y" a W chromosome and the other a Z chromosome.
		The human Y chromosome is unable to recombine with the X chromosome, except for small pieces of pseudoautosomal regions at the telomeres (which comprise about 5% of the chromosome's length).
		When chromosome surveys were first done in the 1960s, it was reported that a higher than expected number of men in prisons were found to have an extra Y chromosome, so that for a while it was thought to predispose a boy to antisocial behavior (and was dubbed the "criminal karyotype").
	en.wikipedia.org /wiki/Y-chromosome (1746 words)

	Cherry Snapper Website
		The Z chromosome also has a number of sites which produce testosterone, but there is not enough testosterone produced in the bloodstream to overcome the development of ovaries and stimulate the development of testicles instead.
		Just how much testosterone is produced by the Z chromosomes is still a question, but it is enough that when the hornorum males are used to fertilize female fish of another species which carry a different sort of chromosome (generally the X chromosome) almost 100% of the fish produced by this breeding are male.
		The Y chromosome is a particularly potent producer of testosterone and when combined with most X chromosomes still produces enough total testosterone to switch the balance in the blood stream of the developing fish to stimulate the development of testicles.
	www.cherrysnapper.com /Species/0.html (3091 words)

	Finch Genetics -FinchInfo.com-
		This is a chromosome pair or homologous pair, consisting of two chromosomes (numbers 1 and 2) which are similar in form and function.
		Here is the chromosome pair again, only this time the chromosomes do not contain the exact same gene on locus "A." When this occurs, the gene pair is called heterozygous, and the bird is said to be "single-factor" for the white gene (or, respectively, single-factor for the purple gene).
		The expression of a genotype in the appearance of an organism; the observed trait.
	www.finchinfo.com /genetics (1656 words)

	Genetics Primer
		Two chromosomes that are the same size, shape, length and contain the same genetic information are called homologous chromosomes.
		The female chromosomes are represented by the letters Z and W. The Z chromosome in the female is homologous to the Z chromosome in the male but the W chromosome is completely different.
		The W chromosome does not contain the same genetic information and is a different size and shape.
	home.earthlink.net /~100chickens/id5.html (438 words)

	Chapter 3 The Chromosome Theory of Inheritance (Site not responding. Last check: 2007-11-03)
		The probability that anyone specific chromosome that was contributed from the father ends up in a particular haploid spore is 1/2.
		To calculate frequencies, the probability of a Z egg is Y2 and the probability of a W egg is Y2.
		If it is a Z egg, then there is a 1/3 probability that one of the 3 polar bodies will be Z, and a 213 probability that it will be W (because you already used up a Z in the egg).
	www.bio.unc.edu /courses/2004Fall/biol050-007/Homework/Chap3answers.htm (2709 words)

	BioMed Central \| Full text \| Sex-dependent gene expression in early brain development of chicken embryos
		Among the 'female genes', three are located on the female-specific W chromosome (Table 2), one on the Z chromosome (Table 2) and 11 on autosomes, whereas for four genes the location is unknown (Table 1).
		Among the 114 'male genes', 61 are located on the Z chromosome (Table 2) and 29 on autosomes, and for another 29 genes the location is unknown (Table 1).
		That such a large proportion of genes located on the sex chromosomes (Z and W) were identified as differentially expressed in the chicken is therefore intriguing considering the independent evolution and different gene content of the sex chromosomes in birds and mammals [24].
	www.biomedcentral.com /1471-2202/7/12 (6321 words)

	Old World Aviaries: A brief review of avian genetics
		This is because the donkey's and horse's chromosome numbers differ by one but their genetics are similar--close enough to produce offspring but different enough for the offspring to be infertile.
		With birds most species are confined to their genus because chromosome numbers are more likely to vary among genera, and even if the numbers are the same, the gene patterns on the chromosomes can differ significantly.
		Therefore, it is not expressed because the other Z chromosome carries the normal, dominant, gray gene, resulting in a gray bird.
	www.oldworldaviaries.com /text/styles/genetics.html (1560 words)

	MCDB 2150 -- Lecture 29
		The hemizygous female always exhibits the pattern dictated by her one and only Z chromosome, while the phenotype of the male is determined by the dominance relationship of the two alleles carried on his Z chromosomes.
		Early in development, there is random inactivation of one of the X chromosomes in each somatic cell of female embryos, which is retained in all of the daughter cells arising from each of the initially X-inactivated cells.
		Human sex chromosome aneuploidies: Despite their major structural differences, X and Y chromosomes contain pseudoatosomal regions that permit them to come together as "homologous pairs" during meiotic prophase and to be independently assorted to the poles during the first meiotic division in much the same manner as autosomes.
	www.colorado.edu /MCDB/MCDB2150Fall/notes99/99L29.html (2774 words)

	[No title]
		The sex chromosomes are unique in that there are two types, a long sex chromosome, the Z chromosome, and a short sex chromosome, the W chromosome.
		Genes responsible for sex-linked traits are on the long sex chromosome, Z, but not the short sex chromosome, W. For that reason, I prefer to use a blank or underscore to represent the missing gene when representing the genes (genotype) of the female.
		The rate of crossover events occuring between a gene at locus A and a gene at locus B is proportional to the distance between the two genes on the chromosome (or equivalently, the crossover rate is proportional to the distance between the two loci).
	marsa_sellers.tripod.com /geneticspages/page1.html (4971 words)

	Molecular Genetics Research
		The Z chromosome sequences contained shorter repeat types than the rest of the chromosomes in addition to a higher abundance of AT-rich repeats.
		The Z chromosome carries important traits of economic value as well as genes for various phenotypic traits, but, based on its relative size, only 2% of molecular information based on its relative size is known.
		The linkage distances obtained suggested that the markers were distributed throughout the Z chromosome.
	www.in.embnet.org /lmgsga.html (1329 words)

	Discovery Channel :: News :: Study: Platypus Retains Bird Sex Link
		The different fluorescent colors enabled the researchers to both identify and track the chromosomes and their involvement in meiosis, which is the process of cellular division that produces eggs in females and sperm in males.
		In birds, the male and female chromosomal roles somewhat are reversed, as female birds carry two different chromosomes, called Z and W. The overall bird system is called ZZ/ZW.
		Notably, the researchers discovered that X5 resembles the bird Z chromosome in terms of appearance and the signaling of associated genes.
	dsc.discovery.com /news/briefs/20041025/platypus.html (721 words)

	Cathepsin L Stabilizes the Histone Modification Landscape on the Y Chromosome and Pericentromeric Heterochromatin -- ...
		Chromosomes were first stained with anti-H3me3K9 antibodies (red) and then subjected to FISH with Y-specific probe (green) and counterstained with Hoechst (blue).
		as chromosome instability and aberrant segregation or down-regulation
		Analysis of a malsegregating mouse Y chromosome: evidence that the earliest cleavage divisions of the mammalian embryo are non-disjunction-prone.
	mcb.asm.org /cgi/content/full/26/11/4172 (8087 words)

	Breeding For Sex Linked Traits (Site not responding. Last check: 2007-11-03)
		The male has two z chromosomes and on each chromosome is a gene for gold.
		The female has one Z chromosome and a silver gene is found on her Z chromosome.
		The mothers Z chromosome will have a silver gene so the male chicks will be silver (S/s+) from the silver gene they received from the mother.
	home.earthlink.net /~100chickens/id40.html (636 words)

	Brown Base Colors
		In addition, since the gene for brown is located on a sex chromosome and since a hen only has one Z then brown hens are symbolized as b/- to denote only one color gene and /- one sex chromosome.
		Their difference is in the number of sex chromosomes and alternately the number of color genes to be found there.
		Since a single color gene resides on each Z chromosome a cock will have two genes for color while a hen is limited to only one.
	www.angelfire.com /ga/huntleyloft/brown.html (1775 words)

	Dr. Siwo de Kloet
		Tinamous possess a W sex-chromosome, intermediate in heterochromatization between the largely euchromatic W chromosome of the ratites and the highly condensed W chromosome of the neognathous birds.
		This suggests that cessation of recombination at the spindlin locus of the ancestral W and Z chromosomes of the tinamiformes and the neagnathous avian species were independent events.
		A repetitive DNA sequence on the W chromosome of owls (Strigiformes) with sequence similarity to the chicken W chromosomal repeat.
	www.avianbiotech.com /drdeKloet.htm (1682 words)

	Evolution of the avian sex chromosomes from an ancestral pair of autosomes -- Fridolfsson et al. 95 (14): 8147 -- ...
		Note that the orientation of the W chromosome is not known; the signals of CHD1W and ATP5A1W are both from one of the chromosome ends.
		The location of Z chromosome genes have been drawn to scale according to the recombination distances separating them in the linkage map derived from the East Lansing reference population.
		The gene content of the eutherian X chromosome is conserved essentially in toto, as predicted by Ohno (2).
	www.pnas.org /cgi/content/full/95/14/8147 (4671 words)

	Hens, cocks and avian sex determination
		In mammals, for instance, the presence of the male-specific Y chromosome confers maleness, whereas in Drosophila melanogaster and Caenorhabditis elegans it is the number of X chromosomes that matters.
		Although there is a small pseudoautosomal region on Z and W with an obligate crossing-over at meiosis, most of the W chromosome does not recombine (this is analogous to the situation in X and Y of mammals).
		It has not been clear whether it is the presence of the female-specific W chromosome that triggers female development (Figure 1A), or the dose of Z chromosome that confers maleness (Figure 1B).
	www.nature.com /embor/journal/v2/n3/full/embor459.html (3559 words)

	Glossary of biotechnology and genetic engineering (Site not responding. Last check: 2007-11-03)
		In most animals, the female has two, and the male has one X chromosome.
		The opposite occurs in birds, in which the equivalent is the Z chromosome.
		In X-linked recessive conditions, a normal female "carrier" passes on the allele on her X chromosome to an affected son.
	www.fao.org /DOCREP/003/X3910E/X3910E27.htm (238 words)

	Wpkci, Encoding an Altered Form of PKCI, Is Conserved Widely on the Avian W Chromosome and Expressed in Early Female ...
		Locations of Wpkci on the nonheterochromatic end of the W chromosome and chPKCI near the centromere on the long arm of the Z chromosome are illustrated in B. The chPKCI locus on the Z chromosome was assigned by measuring 122 FISH figures.
		its mammalian homologue on chromosome 9 is implicated in the differentiation
		chPKCI is a single-copy gene on the Z chromosome.
	www.molbiolcell.org /cgi/content/full/11/10/3645 (9437 words)

	W chromosome - definition from Biology-Online.org (Site not responding. Last check: 2007-11-03)
		The W chromosome causes the individual to become female in bird species.
		It is part of the WZ set of sex chromosomes, where the female has one W chromosome and one z chromosome, and the male has two Z chromosomes.
		The equivalent of the mammal Y chromosome that is found in birds, like the comparison of X and Z chromosomes respectively.
	www.biology-online.org /dictionary/W_chromosome (161 words)

	[No title]
		If the mother contributes a long sex chromosome, Z, to the unfertilized egg, the chick from that egg will be male because it will have two long sex chromosomes after fertilization, since it always gets a long sex chromosome from the father.
		To breed a trait that is present in male chicks and absent in female chicks, the trait must be dominant and on the Z sex chromosome (sex-linked), the female parent must have the trait and the male should be lacking the trait.
		The B gene is on the Z choromosome so the male Barred Rocks have two B genes while the females have one.
	marsa_sellers.tripod.com /geneticspages/page2.html (5420 words)

	The Learning Center - Genetics 501
		In snakes, it's the 'W' and 'Z' chromosomes (ZZ=Male and WZ=female) that are responsible for sex determination.
		In males, two copies of the 'Z' chromosome are present and the usual genetic rules apply to all loci contained within.
		However in females, those loci in the 'Z' chromosome corresponding to the missing loci from the 'W' chromosome will necessarily contain only one allele.
	www.vmsherp.com /LCGenetics501.htm (1002 words)

	Comparative FISH mapping on Z chromosomes of chicken and Japanese quail
		GHR and PRLR were situated close to each other on the short arm of the chicken Z chromosome, as are their counterparts on human chromosome 5.
		Thus, the present results indicate the presence of conserved synteny between the chicken Z chromosome and human chromosomes 5 and 9.
		The results support the notion that the avian Z chromosome and the mammalian X chromosome did not evolve from a common ancestral linkage group.
	content.karger.com /ProdukteDB/produkte.asp?Doi=15386 (304 words)

	Sex Linkage (Site not responding. Last check: 2007-11-03)
		In mammals, this is the X chromosome (one copy in males, two in females).
		In birds, this is the Z chromosome (one copy in females, two in males).
		These predictions agree with the data, so tooth color is controlled by a gene on the X chromosome and the green mutant allele is dominant to the white wild-type allele.
	web.mit.edu /esgbio/www/mg/sexlinkage.html (667 words)

	The Classroom @ The Coop
		Males have two Z sex chromosomes and females have one Z and one W chromosome.
		If a zygote inherits the W chromosome it is female, and if a zygote inherits the Z chromosome it is a male.
		The hybrid females have only one Z chromosome and it is silver-barred.
	www.the-coop.org /wwwboard/discus/messages/15/5034.html (672 words)

	Identification of the Sex of a Wide Range of Carinatae Birds by PCR Using Primer Sets Selected from Chicken EE0.6 and ...
		Chicken spindlin genes on W and Z chromosomes: transcriptional expression of both genes and dynamic behavior of spindlin in interphase and mitotic cells.
		Differentiation of Z and W chromosomes revealed by replication banding and FISH mapping of sex-chromosome-linked DNA markers in the cassowary (Aves, Ratitae).
		Molecular characterization and cytological mapping of a non-repetitive DNA sequence region from the W chromosome of chicken and its use as a universal probe for sexing Carinatae birds.
	jhered.oxfordjournals.org /cgi/content/full/92/4/315 (3355 words)

	Understanding Genetics: Human Health and the Genome
		The difference is that the chromosomes are called W and Z. And that a W and a Z make a girl and two Z chromosomes make a boy.
		One candidate gene is the DMRT1 gene found on the Z chromosome although this hasn’t been confirmed yet.
		DMTR1 is on E9, one of the chromosomes that if you have two of them, you are a girl platypus.
	www.thetech.org /exhibits/online/ugenetics/ask.php?id=178 (787 words)

	Medical Term Medical Dictionary Medicine Online
		Z chromosome: This is a sex chromosome in certain animals likes chickens, turkeys, and moths.
		But in animals with a Z chromosome, males are ZZ and females are WZ.
		Zinc is a constituent of many enzymes that permit chemical reactions to proceed at normal rates.
	www.medicineonline.com /dictionary/dict_Z.html (470 words)

	Human Y Chromosome, Sex Determination, and Spermatogenesis--A Feminist View -- Marshall Graves 63 (3): 667 -- Biology ...
		that the Y chromosome is a "wimp," a pale shadow of its former
		The Y chromosome is unique in that it is found only in males.
		Embryonic growth and the evolution of the mammalian Y chromosome.
	www.biolreprod.org /cgi/content/full/63/3/667/b (6931 words)

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