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Topic: Chromosome


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DNA

In the News (Tue 19 Mar 19)

  
  Chromosome fusion
The function of the telomere is to protect the ends of the chromosomal DNA strands during replication.
However, in human chromosome 2, there is strong evidence for chromosome fusing in that there is a pretelomeric sequence, a telomeric sequence, an inverted telomeric sequence and an inverted pretelomeric sequence in that order in the middle of the chromosome.
The evidence that human chromosome 2 is a fusion of two of the common ancestor's chromosomes is overwhelming.
www.evolutionpages.com /chromosome_2.htm   (913 words)

  
 Human Chromosome Launchpad
This site is provided as a single-source launchpad to information about each human chromosome.
Choose databases and other information resources by "pointing and clicking" on one of the pictured chromosomes or by using the list of links below.
Each chromosome page provides links to gene maps, sequences, associated genetic disorders, nonhuman genetic models, identified genes, research efforts and laboratories, and other information as available.
rd.business.com /index.asp?epm=s.1&bdcq=Chromosome&bdcr=5&bdcu=http://www.ornl.gov/hgmis/launchpad/&bdct=20080516143043&bdcp=&partner=2662601&bdcs=nwuuid-2662601-13FF2BC1-FD99-EAF4-9A4B-68ED105EA68F-ym   (187 words)

  
  Human Genome Landmarks Poster
These regions reflect the unique patterns of light and dark bands seen on human chromosomes that have been stained to allow viewing through a light microscope.
Chromosomal regions that vary in staining intensity and are sometimes called heterochromatin (meaning "different color").
(e.g., on chromosome 21) denote variable regions, called stalks, that connect a very small chromosome arm (a "satellite") to the chromosome.
www.ornl.gov /sci/techresources/Human_Genome/posters/chromosome/chooser.shtml   (383 words)

  
  Chromosome - MSN Encarta
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.
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).
encarta.msn.com /encnet/refpages/RefArticle.aspx?refid=761566230   (976 words)

  
  Chromosome - Wikipedia, the free encyclopedia
During mitosis (cell division), the chromosomes are condensed and a spindle composed of microtubules is formed.
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.
en.wikipedia.org /wiki/Chromosome   (1672 words)

  
 Y chromosome - Wikipedia, the free encyclopedia
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 (sometimes called TDF gene), which seems to determine the sex in primates.
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").
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 son.
en.wikipedia.org /wiki/Y_chromosome   (2005 words)

  
 genome.gov | Chromosome Abnormalities Fact Sheet
One set of 23 chromosomes is inherited from the biological mother (from the egg), and the other set is inherited from the biological father (from the sperm).
To help identify chromosomes, the pairs have been numbered from 1 to 22, with the 23rd pair labeled "X" and "Y." In addition, each chromosome arm is defined further by numbering the bands that appear after staining; the higher the number, the further that area is from the centromere.
The first 22 pairs of chromosomes are called "autosomes" and the final pair is called the "sex chromosomes." The sex chromosomes an individual has determines that person's gender; females have two X chromosomes (XX), and males have an X and a Y chromosome (XY).
www.genome.gov /11508982   (1119 words)

  
 chromosome. The Columbia Encyclopedia, Sixth Edition. 2001-05
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.
When the germ cells divide in the two-step process of meiosis, the chromosomes are separated in such a way that each daughter cell receives a haploid (half the diploid) number of chromosomes.
Chromosomes appear microscopically as a linear arrangement of genes, the factors that determine the inherited characteristics of all living organisms.
www.bartleby.com /65/ch/chromoso.html   (322 words)

  
 Chromosome 22 - Genetics Home Reference
Chromosome 22 is one of the 23 pairs of chromosomes in humans.
Chromosome 22 is the second smallest human chromosome, spanning about 50 million base pairs (the building blocks of DNA) and representing between 1.5 percent and 2 percent of the total DNA in cells.
Genes on chromosome 22 are among the estimated 20,000 to 25,000 total genes in the human genome.
www.ghr.nlm.nih.gov /chromosome=22   (857 words)

  
 genome.gov | Talking Glossary: "chromosome"
Different kinds of organisms have different numbers of chromosomes.
Humans have 23 pairs of chromosomes, 46 in all: 44 autosomes and two sex chromosomes.
Each parent contributes one chromosome to each pair, so children get half of their chromosomes from their mothers and half from their fathers.
www.genome.gov /glossary.cfm?key=chromosome   (105 words)

  
 ABNORMALITIES IN CHROMOSOME STRUCTURE
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.
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.
www.usd.edu /med/som/genetics/curriculum/1ECHROM3.htm   (1824 words)

  
 Chromosome | World of Genetics
Chromosomes contain the genes, or segments of DNA, that encode for proteins of an individual.
Deviations in the number of chromosomes generally occur as a result of the fusion of sex cells (gametes) with the incorrect number of chromosomes during the process of fertilization.
Organisms with structurally altered chromosomes are general the result of a fusion of a sperm cell (spermatocyte) or egg cell (öocyte) that contains a structurally altered chromosome with a normal egg or sperm during conception.
www.bookrags.com /research/chromosome-wog   (752 words)

  
 Chromosome Map
Chromosome 1 is the largest and is over three times bigger than chromosome 22.
Near the center of each chromosome is its centromere, a narrow region that divides the chromosome into a long arm (q) and a short arm (p).
Each chromosome has a distinct banding pattern, and each band is numbered to help identify a particular region of a chromosome.
www.ncbi.nlm.nih.gov /books/bv.fcgi?rid=gnd.chapter.272   (280 words)

  
 Human Chromosomal Abnormalities: Glossary of Terms
Chromosomes are composed primarily of DNA and protein.
Human sperm and ova normally contain only 23 chromosomes, which is the result of the halving of chromosome pairs in meiosis.
a structural modification of a chromosome in which a portion of a chromatid is broken off and attached to a different location on that chromosome or on another chromosome.
anthro.palomar.edu /abnormal/glossary.htm   (3705 words)

  
 Y chromosome - Hutchinson encyclopedia article about Y chromosome   (Site not responding. Last check: )
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)

  
 X chromosome - Genetics Home Reference
The X chromosome is one of the two sex chromosomes in humans (the other is the Y chromosome).
Genes on the X 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=X   (955 words)

  
 Chromosome Information on Healthline
The remaining 46 are autosomes, meaning that they are not sex chromosomes and are present in all somatic cells (i.e., any other body cell that is not a germinal cell for spermatozoa in males or an ovum in females).
The first chromosome observations were made under light microscopes, revealing rod-shaped structures in varied sizes and conformations, commonly J- or V-shaped in eukaryotic cells and ring-shaped in bacteria.
As the centromere is essential for both division and retention of chromosome copies in the new cells, acentric chromosomes will not pass to the daughter cells during the parental cell division.
www.healthline.com /galecontent/chromosome   (1015 words)

  
 Chromosome 1 - Genetics Home Reference
Chromosome 1 is the largest human chromosome, spanning about 247 million base pairs (the building blocks of DNA) and representing approximately 8 percent of the total DNA in cells.
Genes on chromosome 1 are among the estimated 20,000 to 25,000 total genes in the human genome.
A banding pattern is the characteristic pattern of dark and light bands that appears when a chromosome is stained with a chemical solution and then viewed under a microscope.
ghr.nlm.nih.gov /chromosome=1   (384 words)

  
 Introduction to Chromosomes Chromosome Deletion Outreach, Inc.   (Site not responding. Last check: )
This is a simplified introduction to chromosomes and chromosome abnormalities.
Each chromosome arm is defined further by numbering the bands, the higher the number, the further that area is from the centromere.
Chromosome abnormalities can be inherited from a parent, like a translocation, or be 'de novo' (new in that individual).
www.chromodisorder.org /intro.htm   (2170 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.
The primary difficulty with telomeres is the replication of the lagging strand.
www.ndsu.nodak.edu /instruct/mcclean/plsc431/eukarychrom/eukaryo3.htm   (2942 words)

  
 Chromosome Definition   (Site not responding. Last check: )
The generated chromosome moderators rely on implicitly calling corresponding moderators of their gene members and using the same strategy as genes when generating code to handle basic typed data members.
The most important moderator is the chromosome evaluator, since it is used to obtain the fitness score of the solution encoded in the chromosome.
In such a case, the chromosome evaluator is automatically generated to sum the evaluators of its gene members.
www.ceng.metu.edu.tr /~ucoluk/darwin/node8.html   (219 words)

  
 Reference.com/Encyclopedia/Y chromosome
The Y chromosome is one of the two sex chromosomes in humans and most other mammals (the other is the X chromosome).
The chromosome may be used to trace sexes have unpaired X chromosomess; in the other, both females and males have XX.
Human Y chromosome is unable to recombinate with X chromosome, except for small pieces on the ends, which are about 5% of their length.
www.reference.com /browse/wiki/Y_chromosome   (1736 words)

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