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Topic: Y-chromosome

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Chromosome

46,XY

X chromosome

SRY

47,XYY syndrome

Sex chromosome

Cohen Modal Haplotype

Y

Boolean ring

Deoxyribonucleic acid

Haemophilia

Mitochondrial Eve

Allele

Sex

Genetic genealogy

Chromosome - Wikipedia, the free encyclopedia Chromosomes were first observed in plant cells by Swiss botanist Karl Wilhelm von Nägeli (1817-1891) in 1842, and independently, in Ascaris worms, by the Belgian scientist Edouard Van Beneden (1846-1910). Cat-eye syndrome and isodicentric chromosome 15 syndrome are both caused by a supernumerary marker chromosome, as is Pallister-Killian syndrome. Like many sexually reproducing species, humans have special gonosomes (sex chromosomes, in contrast to autosomes for body functions). en.wikipedia.org /wiki/Chromosome   (1702 words)

Y chromosome - Wikipedia, the free encyclopedia 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"). 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. In human genetic genealogy (the application of genetics to traditional genealogy) use of the information contained in the Y chromosome is of particular interest since, unlike other genes, the Y chromosome is passed exclusively from father to sons. en.wikipedia.org /wiki/Y_chromosome   (1981 words)

MSN Encarta - Chromosome In the cells of most organisms that reproduce sexually, chromosomes occur in pairs: One chromosome is inherited from the female parent, and one is inherited from the male parent. Both males and females inherit one sex chromosome from the mother (always an X chromosome) and one sex chromosome from the father (an X in female offspring and a Y in male offspring). This process ensures that each chromosome moves to its proper place during mitosis, when a cell divides to give rise to two cells, and during meiosis, the process of cell division that gives rise to eggs or sperm. encarta.msn.com /encnet/refpages/RefArticle.aspx?refid=761566230   (1021 words)

Y chromosome - Hutchinson encyclopedia article about 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. encyclopedia.farlex.com /Y+chromosome   (370 words)

Human and Ape Chromosomes Since the chromosomes were apparently joined end to end, and the ends of chromosomes (called the telomere) have a distinctive structure from the rest of the chromosome, there may be evidence of this structure in the middle of human chromosome 2 where the fusion apparently occurred. Chromosomes 3, 11, 14, 15, 18, 20, and Y look the same in three of the four species (those three being gorilla, chimps, and humans), and chromosomes 1, 2p, 2q, 5, 7 - 10, 12, and 16 are alike in two species. When the vicinity of chromosome 2 where the fusion is expected to occur (based on comparison to chimp chromosomes 2p and 2q) is examined, we see first sequences that are characteristic of the pre-telomeric region, then a section of telomeric sequences, and then another section of pre-telomeric sequences. www.gate.net /~rwms/hum_ape_chrom.html   (2885 words)

ABNORMALITIES IN CHROMOSOME STRUCTURE In contradistinction, a numerical chromosome abnormality in a child is presumed to be due to a sporadic cell division error and parental chromosome studies are not indicated. Individuals and families have been described with a translocation chromosome abnormality and a concurrent genetic condition; the genetic condition occurring because the chromosome breakpoint is in the midst of a gene. The chromosomes are distributed to the daughter cells by the centromeres which are attached to spindle fibers. www.usd.edu /med/som/genetics/curriculum/1ECHROM3.htm   (1824 words)

DNA Structure, Replication and Eukaryotic Chromatin Structure Eukaryotic chromosomes consist of a DNA-protein complex that is organized in a compact manner which permits the large amount of DNA to be stored in the nucleus of the cell. Telomeres are the region of DNA at the end of the linear eukaryotic chromosome that are required for the replication and stability of the chromosome. In addition to describing the genome of an organism by its number of chromosomes, it is also described by the amount of DNA in a haploid cell. www.ndsu.nodak.edu /instruct/mcclean/plsc431/eukarychrom/eukaryo3.htm   (2942 words)

Chromosome Pairing Very many more chromosomes per cell, a mean of 11.0 compared with a mean of 2.9, were involved in chiasma-associations and a much higher frequency of closed bivalent and of 'pan-handle' trivalents resulted from more intimate pairing. One arm of the chromosome monosomic in the HH line is rather more than twice the length of the other, but the chromosome has not yet been positively identified relative to the numbering based on the variety Chinese Spring. As many as nineteen of the twenty chromosomes of the nulli-haploid have been observed in various associations simultaneously, although never more than nine were involved in associations in the same cell in euhaploids. www.geocities.com /RainForest/1978/Heredity/pairing.htm   (1723 words)

Introduction to Chromosomes Chromosome Deletion Outreach, Inc. Each chromosome arm is defined further by numbering the bands, the higher the number, the further that area is from the centromere. Chromosome analysis is full of exceptions and results that can be difficult to interpret. This is a simplified introduction to chromosomes and chromosome abnormalities. www.chromodisorder.org /intro.htm   (2170 words)

Wired News: Mapping an 'Unlucky' Chromosome Chromosome seven is the home of genes associated with cystic fibrosis, deafness, several cancers and a protein that resists cancer drugs. Whichever count may be correct, chromosome seven is the largest to be fully sequenced thus far. The chromosome seven data from both groups is available for free to anyone on the Internet. www.wired.com /news/technology/0,1282,59563,00.html   (891 words)

chromosome Chromosomes appear microscopically as a linear arrangement of genes, the factors that determine the inherited characteristics of all living organisms. Each of these chromosome numbers is the so-called diploid number, i.e., the number found in the somatic (body) cells and in the germ cells that give rise to the gametes, or reproductive cells. Genetics and Cytology of Chromosome Inversions in Soybean Germplasm. www.infoplease.com /ce6/sci/A0812134.html   (396 words)

Human Chromosomes Chromosome: a very long DNA molecule and associated proteins, that carry portions of the hereditary information of an organism. When they are stained, the mitotic chromosomes have a banded structure that unambiguously identifies each chromosome of a karyotype. A chromosomal DNA molecule contains three specific nucleotide sequences which are required for replication: a DNA replication origin; a centromere to attach the DNA to the mitotic spindle.; a telomere located at each end of the linear chromosome. www.accessexcellence.org /AB/GG/human.html   (189 words)

Chromosome 9 Resource Chromosome 9 is approximately 145 Megabases in length and chiasma counts suggest a genetic length of 116 cM in males. The Sanger centre announced in 1998 that they have designated chromosome 9 as one of their sequencing targets. The Genethon genetic map of chromosome 9 contains 189 markers and estimates the distance as 138.5cM in males and 194.5cM in females, although the distance from the most distal markers to the telomeres is not known. www.gene.ucl.ac.uk /chr9   (135 words)

The Cell Nucleus II This involves the use of DNA or oligonucleotides complementary to a nucleotide sequence on the chromosomes. These modifications create a banding pattern that can be used to identify and characterize individual chromosomes. In the normal, unstripped chromosome, the double stranded DNA is wrapped around sets of 8 histones to form a 10 nm filament. cellbio.utmb.edu /cellbio/nucleus2.htm   (1412 words)

The Y chromosome as a marker for the history and structure of human populations Particular sub-sets of Y chromosomes may predispose to infertility, or to male-specific cancers, and thus it may be possible to identify the influence of selection on Y haplotypes (19 - 21), as we have done for one class of XX male (22). We have coordinated a large collaborative study to test hypotheses for the origins of modern European populations from a Y chromosome perspective (9, 10), interpreting patterns of diversity in terms of both the impact of the arrival of agriculture in Europe, and of linguistic and geographical barriers to gene flow. The slowly mutating markers define 'haplogroups' of chromosomes related by descent, and the microsatellites and minisatellite can then be used to examine diversity within these; mutation analysis at MSY1 provides a tool which should allow us to estimate ages for the most recent common ancestors of groups of chromosomes, as an alternative to microsatellites (7). www.le.ac.uk /genetics/maj4/project.html   (1397 words)

CarlZimmer.com From his father, a boy inherits a chromosome called Y, and from his mother, a chromosome called X. During the formation of sperm, as the other chromosomes shuffle their genes, only a small section of the Y chromosome exchanges bits of material with its partner. Of the twenty-three pairs of chromosomes carried by men in the nucleus of their cells, twenty-two consist of partners identical in length, shape, and sequence of genes. One possible explanation for this speed is that one of the genes on Adam’s Y chromosome had a mutation that gave it an evolutionary edge, and natural selection then drove its spread. www.carlzimmer.com /articles/2001/articles_2001_AdamEve.html   (2229 words)

Dr Chromo's school: chromosomes structure A chromosome is the visible state of genetic material during a phase of the division of the cell Chromosomes, genes, genotypes and other concepts are explained in the MBN CD-ROM... A model of a chromosome during metaphase is displayed on the left: Click on it to see the legend (don't forget to come back). www.rothamsted.bbsrc.ac.uk /notebook/courses/guide/chromo.htm   (368 words)

Sex Chromosomes In all the cells of the extraembryonic membranes, it is father's X chromosome that is inactivated. In a given cell, which of a female's X chromosomes becomes inactivated and converted into a Barr body is a matter of chance (except in marsupials like the kangaroo, where it is always the father's X chromosome that is inactivated). Although the male fruit fly, Drosophila melanogaster, is X-Y, the Y chromosome does not dictate its maleness but rather the absence of a second X. In birds and moths, the male has two of the same chromosome (designated ZZ), whereas the female has "heterogametic" chromosomes (designated Z and W). users.rcn.com /jkimball.ma.ultranet/BiologyPages/S/SexChromosomes.html   (1649 words)

Chromosomes While they are still attached, it is common to call the duplicated chromosomes sister chromatids, but this should not obscure the fact that each is a bona fide chromosome with a full complement of genes. The packing reaches its extreme during mitosis when a typical chromosome is condensed into a structure about 5 µm long (a 10,000-fold reduction in length). For most of the life of the cell, chromosomes are too elongated and tenuous to be seen under a microscope. users.rcn.com /jkimball.ma.ultranet/BiologyPages/C/Chromosomes.html   (821 words)

Genetics Glossary Ca-Cn The theory that chromosomes are linear sequences of genes. Any distinct and heritable feature of chromosome structure that can be used to follow (usually by microscopy) that chromosome or chromosome region in breeding experiments. The unifying theory stating that inheritance patterns may be generally explained by assuming that genes are located in specific sites on chromosomes. helios.bto.ed.ac.uk /bto/glossary/c.htm   (1753 words)

MedlinePlus Medical Encyclopedia: Chromosome 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. Chromosomes are long pieces of DNA contained in the nucleus of cells. In humans, the nucleus of each cell has 23 pairs of chromosomes (46 total chromosomes). www.nlm.nih.gov /medlineplus/ency/article/002327.htm   (355 words)

Chromosome definition - Medical Dictionary definitions of popular medical terms The chromosome of the mitochondrion, which is in the cytoplasm of the cell, is a somewhat different story. A few types of major chromosomal abnormalities, including missing or extra copies or gross breaks and rejoinings (translocations), can be detected by microscopic examination; Down's syndrome, in which an individual's cells contain a third copy of chromosome 21, is diagnosed by karyotype analysis. The foregoing definition and discussion pertain to the chromosomes in the nucleus of the cell. www.medterms.com /script/main/art.asp?articlekey=14018   (382 words)

CDO Chromosome Deletion Outreach, Inc. Chromosome Deletion Outreach, Inc. is a non-profit organization, founded, supported, and run by parents just like you. Our children are affected by a wide range of chromosome disorders, including deletions, duplications, trisomies, inversions, translocations, and rings. Your support of CDO will help promote research and a better understanding of our children’s rare chromosome disorders. www.chromodisorder.org   (204 words)

NPR : As Y Chromosome Shrinks, End of Men Pondered In paired chromosomes, that means that if there is a mistake on one chromosome, a cell can always get the correct gene sequence from the other chromosome. In men, the 23rd chromosome is made up of an X chromosome and a Y chromosome. All Things Considered, December 13, 2004 · It takes a man to carry a Y chromosome, and it takes the Y chromosome to make sperm, which is necessary for human reproduction. www.npr.org /templates/story/story.php?storyId=4225769   (661 words)

genome.gov Talking Glossary: "chromosome" Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers. Eric Green, of the National Human Genome Research Institute's Genome Technology Branch, defines chromosome. autosome, birth defect, cell, deoxyribonucleic acid (DNA), gene, nucleus, protein, sex chromosome www.genome.gov /glossary.cfm?key=chromosome   (105 words)

Human Genome Landmarks Poster (e.g., on chromosome 21) denote variable regions, called stalks, that connect a very small chromosome arm (a "satellite") to the chromosome. Click on any chromosome below to see a list of selected traits and disorders associated with that chromosome. The Human Genome Landmarks poster is a 24" by 36" wall poster that lists selected genes, traits, and disorders associated with each of the 24 different human chromosomes. www.ornl.gov /sci/techresources/Human_Genome/posters/chromosome/chooser.shtml   (383 words)

MedlinePlus Medical Encyclopedia: Fragile X syndrome chromosome analysis A normal result would indicate that less than 4% of the cells has a constricted section on the long arm of the X chromosome. If more than 4% of the cells evaluated test positive for fragile X chromosomes, fragile X syndrome is indicated. MedlinePlus Medical Encyclopedia: Fragile X syndrome chromosome analysis www.nlm.nih.gov /medlineplus/ency/article/003413.htm   (784 words)

LLNL Human Genome Center Sequence analysis of a variety of regions from chromosome 19 indicate that it is indeed gene-rich, even in regions expected to be gene-poor due to a paucity of genetic markers. This chromosome is GC-rich (and thus, potentially gene-rich) and contains a large number of clustered gene families, several of which are targets for genomic sequencing. In addition to genomic sequence, over 50 complementary DNA clones (cDNAs) from genes on human chromosome 19 were fully sequenced and submitted to public sequence databases. bbrp.llnl.gov /bbrp/genome/genome.html   (321 words)

X-chromosome Dosage Compensation Whether the pieces are large or small, or derived from one or another chromosome region, the result is the same: the genes, both those originally of the X and those of other chromosomes, still have the same dosage effects as they did in their old positions. The chromosome constitution of a series of these is represented on the upper row of cytological diagrams in this figure. And that the two doses in the male cause even more abnormality than three doses of the same section of chromosome in the female is also to be expected, if the degree of effect depends on the ratio of primary genes to compensators. post.queensu.ca /~forsdyke/xchromos.htm   (12811 words)

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