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Topic: Y chromosome


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Sex

  
  Y chromosome - Genetics Home Reference
The Y chromosome is one of the two sex chromosomes in humans (the other is the X chromosome).
Genes on the Y chromosome are among the estimated 20,000 to 25,000 total genes in the human genome.
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).
ghr.nlm.nih.gov /chromosome=Y   (784 words)

  
  Y Chromosome
The Y chromosome is one of the two sex chromosomes in humans (the other is the X chromosome).
Genes on the Y chromosome are among the estimated 20,000 to 25,000 total genes in the human genome.
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).
www.net-one.net /ychrom.htm   (1367 words)

  
 Y chromosome
The Y chromosome is the smallest of all the mammalian chromosomes and is considered to be largely inert (that is, without direct effect on the physical body), apart from containing the genes that control the development of the testes.
The Y chromosome is shorter than the X. Genes on these chromosomes determine a person's sex (sex determination).
In 1989 the gene determining that a human is male was found to occur on the X as well as on the Y chromosome; however, it is not activated in the female.
www.tiscali.co.uk /reference/encyclopaedia/hutchinson/m0007893.html   (465 words)

  
 Genetics and Identity   (Site not responding. Last check: )
The 23rd pair is either a pair of X chromosomes, meaning the individual is female, or an X chromosome and a Y chromosome, meaning the individual is male.
Because the Y chromosome cannot easily swap information with the X chromosome, the Y chromosome in a man's sperm will be an almost exact copy of the Y chromosome in his body's cells.
Polymorphisms in a man's Y chromosome are also passed directly on to his sons, and then on to their sons and so on.
www.bioethics.umn.edu /genetics_and_identity/background.html   (778 words)

  
 Y chromosome   (Site not responding. Last check: )
In scientific circles, the Y chromosome —— the essence of masculinity —— is scorned as the runt of the human genetic family, so henpecked by mutations that it is wasting away.
The relationship between the Y chromosome, which triggers male development in an embryo, and the X chromosome, which is responsible for female development, is a mystery that has been unfolding for more than 240 million years.
For the Y chromosome, these extensive repetitive stretches of gene sequences serve as templates to repair and proofread its own DNA, almost as if each were a gene on a separate matching chromosome.
www.clt.astate.edu /mgilmore/y_chromosome.htm   (1194 words)

  
 Y chromosome Summary
Many of the genes on the Y chromosome are involved in male sexual determination and development; two genes of particular importance for sex determination are the SRY gene (in humans and other primates) and UBE1 (in most other mammals).
The X and Y chromosome diverged around 300 millions years ago [1] when some reptile, which was a distant ancestor of all mammals, developed a gene which makes all its owners to be males.
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").
www.bookrags.com /Y_chromosome   (3301 words)

  
 The Y Chromosome in the study of human evolution, migration and prehistory
Since the Y chromosome, unlike the autosomes in the other 22 pairs, does not exchange letters with a partner (except for the comparatively small pseudoautosomal regions), those mistakes are the only changes which are passed on to the next generation.
In the Y chromosome's passage through the generations, changes occur randomly in its junk DNA and so the Y chromosomes of the contemporary population retain a record of their passage through time: they can reveal the paternal genealogy of their owners and the relationships between different groups of individuals.
Because most of the Y chromosome does not exchange DNA with a partner, a further benefit of using it to study evolution is that all the markers are joined one to another along its entire length.
www.ramsdale.org /dna13.htm   (3400 words)

  
 Y Chromosome
The other chromosome of the pair in males is called the Y chromosome and is much smaller than the X. Biologists thought until very recently that the Y chromosome had only a few active genes.
Because there is no other Y to serve as a pairing partner in meiosis, most of its genes had been thought to have decayed, the victims of Muller’s ratchet, leaving the Y chromosome a genetic wasteland with only a very few active genes surviving on it.
One of the few genes documented to be on the Y chromosome (it’s inherited, seen in families that carry it in all males and no females) causes very hairy ears.
www.txtwriter.com /Onscience/Articles/ychromosome.html   (1177 words)

  
 Y chromosome definition - Medical Dictionary definitions of popular medical terms easily defined on MedTerms
Once thought to be a genetic wasteland, the Y now is known to contain at least 20 genes, some of them unique to the Y including the male-determining gene and male fitness genes that are active only in the testis and are thought responsible for the formation of sperm.
The Y is a useful chromosome for tracking men because it is transmitted unchanged from father to son.
The Y escapes the intergenerational shuffle (recombination) that affects genes on the X chromosome and the remainder of the genome.
www.medterms.com /script/main/art.asp?articlekey=6049   (378 words)

  
 Y Chromosome
The human Y chromosome has now been sequenced and published in the June 19, 2003 issue of Nature.
The euchomatic part of the X chromosome is six times longer than that of Y. Few genes on the X have an active counterpart on the Y, and the majority of these are contained in regions where XY homology (similar structure) is of relatively recent origin.
At the tip of the long arm of X and Y is a second pseudoautosomal region, the 330 kb PAR2, which was created by duplication of material from X to Y since the divergence of human and chimpanzee lineages about 6 million years ago.
universe-review.ca /R11-14-Ychromosome.htm   (1906 words)

  
 Dr. Koop - Chromosome
Chromosomes are long pieces of DNA contained in the nucleus of cells.
Mitochondria have their own DNA strand, sometimes called "the 47th chromosome." All of your genes are contained within these 46 nuclear chromosomes and 1 mitochondrial chromosome.
The father may contribute an X or a Y. Therefore, it is the father that determines the gender of the child.
www.drkoop.com /ency/93/002327.html   (360 words)

  
 NOVA Online | Lost Tribes of Israel | Why the Y Chromosome
A karyotype, or chromosomal representation, of the 23 pairs of chromosomes in a human male.
Unlike other chromosomes, the genetic material on the Y chromosome is not mixed with each new generation.
The information carried on the Y chromosome travels from father to son as a nearly exact copy of itself.
www.pbs.org /wgbh/nova/israel/familyy.html   (369 words)

  
 CNN.com - Health - Scientists close to deciphering Y chromosome - October 30, 2000
The idea that men had their own chromosome was recognized in the early 1920s, and the Y was one of the first to be identifiable under a microscope.
The ancestors of the human X and the Y were a pair of identical chromosomes.
That's why the Y chromosome is only one-third the size of the X. For a gene, Page notes, the Y chromosome is a very hard place to make a living.
archives.cnn.com /2000/HEALTH/men/10/30/guy.chromosome.ap   (1783 words)

  
 Science Spectra [Article]
Since the Y chromosome, unlike the autosomes in the other 22 pairs, does not exchange letters with a partner (except for the comparatively small pseudoautosomal regions), those mistakes are the only changes which are passed on to the next generation.
In the Y chromosome's passage through the generations, changes occur randomly in its junk DNA and so the Y chromosomes of the contemporary population retain a record of their passage through time: they can reveal the paternal genealogy of their owners and the relationships between different groups of individuals.
Because most of the Y chromosome does not exchange DNA with a partner, a further benefit of using it to study evolution is that all the markers are joined one to another along its entire length.
www.ucl.ac.uk /tcga/ScienceSpectra-pages/SciSpect-14-98.html   (3507 words)

  
 Y Chromosome | World of Genetics
The Y is usually the smaller of the two, though the size and shape may vary.
A quick determination about the presence or absence of a Y chromosome in a newborn with ambiguous genitalia can be made by examining metaphase cells for this bright staining region.
The Human Genome Project has confirmed that the Y chromosome is the smallest of the set, with the fewest number of base pairs, only 21.8 Mb, and less than 30% of the known genes of the second shortest chromosome.
www.bookrags.com /research/y-chromosome-wog   (668 words)

  
 MedlinePlus Medical Encyclopedia: Chromosome
Chromosomes are long pieces of DNA contained in the nucleus of cells.
Mitochondria have their own DNA strand, sometimes called "the 47th chromosome." All of your genes are contained within these 46 nuclear chromosomes and 1 mitochondrial chromosome.
The father may contribute an X or a Y. Therefore, it is the father that determines the gender of the child.
www.nlm.nih.gov /medlineplus/ency/article/002327.htm   (355 words)

  
 Study Suggests 'Y' the Male Chromosome Will Endure
Chromosomes are long strands of DNA that contain the genes instructing cells how to make RNA and proteins, the stuff of life.
When this occurs in the 22 matched pairs of chromosomes, or in the X-X pair that women possess, a damaged gene in one member of the pair can be cut out and replaced with a good one in the other member.
But men are X-Y. Their Y chromosome never has a "brother" to recombine with, so this kind of repair can't happen.
www.washingtonpost.com /wp-dyn/content/article/2005/09/04/AR2005090400867.html   (559 words)

  
 DNA.gov: Y Chromosome   (Site not responding. Last check: )
The Y chromosome DNA testing enables examination of the male-specific portion of biological evidence.
Y chromosome analysis can also benefit missing persons investigations as it extends the range of potential reference samples.
Since fathers pass their Y chromosome onto their sons unchanged (except for an occasional mutation), all males in a paternal lineage will possess a common Y chromosome haplotype.
dna.devis.com /research/ychromosome_research   (772 words)

  
 The Y chromosome as a battle ground for sexual selectionE
Other genes on the Y chromosome, whose presence has been either inferred or actually demonstrated, include several that might also be important in sexual selection, such as those related to the control of embryonic growth, stature and the development of teeth.
Genes in the nonrecombining region of the Y chromosomes of mammals.
For those genes on the Y chromosome that have homologues on the X chromosome, it is still not obvious whether there are any genes that are conserved across all mammals, because results are still fragmentary (Fig.
cas.bellarmine.edu /tietjen/Ecology/y_chromosome_as_a_battle_ground_.htm   (3590 words)

  
 Arctic Social Sciences - Arctic Studies Center
The Y chromosome is the male counterpart to mtDNA in that it is inherited from father to son without recombination with the X chromosome.
One of our research goals is to compare Y chromosome data from New World populations with those from Siberian and Asian populations to test these varied hypotheses.
We have been studying the geographic distribution of a Y chromosome marker that has turned out to be particularly interesting for questions about the peopling of the Americas.
www.mnh.si.edu /arctic/html/peopling_siberia.html   (1739 words)

  
 genome.gov | 2003 Release: Mechanism Preserves Y Chromosome Gene
All other chromosomes occur in pairs and preserve genetic integrity by exchanging information with matching genes on the homologous chromosome, a process called "crossing over." But the Y chromosome lacks that option, being the only chromosome that is unpaired.
The extensive use of gene conversion appears to play a role in the ability of the Y chromosome to edit out genetic mistakes and maintain the integrity of the relatively few genes it carries.
The sequencing work on the Y chromosome was carried out at the Genome Sequencing Center at the Washington University School of Medicine as part of the Human Genome Project, which receives substantial funding from NHGRI.
www.genome.gov /11007628   (694 words)

  
 Human Y chromosome preserves itself better than the chimp Y
By using human and chimpanzee Y chromosomes as a genetic fossil record to examine our past, scientists have seen a surprising difference in the way the male-making chromosomes from the two species cope with the inexorable pressures of evolution.
The Y chromosome genes the researchers studied occur in single copies, and make substances used throughout the body to perform basic functions in cells.
By examining and comparing the Y chromosomes from both species, "we're getting a gene catalog of the common ancestor's Y chromosome" even though that ancestor lived long ago and cannot be studied directly.
www.eurekalert.org /pub_releases/2005-08/hhmi-hyc082905.php   (697 words)

  
 Y chromosome at AllExperts
The Y chromosome is one of the two sex chromosomes in humans and most other mammals (the other is the X chromosome).
Many of the genes on the Y chromosome are involved in male sexual determination and development; the most important of them is the SRY gene, which seems to determine the sex in primates.
Findings were confirmed by comparing similar regions of the Y chromosome in humans to the Y chromosomes of chimpanzees, bonobos (the pygmy chimpanzee) and gorillas.
en.allexperts.com /e/y/y/Y_chromosome.htm   (1890 words)

  
 HHMI News: Mutation on Y Chromosome Stops Sperm Production
For now only about 20 percent of cases of male infertility can be traced either to the loss of a large chunk of the male Y chromosome, or to some other large chromosome abnormality, such as the presence of a second X chromosomes in a male.
He first determined the entire DNA sequence for a region of the Y chromosome that is missing in a number of infertile males.
The latter task will not be easy, as some genes on the Y chromosome come in multiple similar versions that confuse analysis, but Page's job will be made easier by the determination of the complete sequence of the Y chromosome.
www.hhmi.org /news/page3.html   (872 words)

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