• Each organism of a species is normally characterized by the same number of chromosomes in its somatic cells, 46 being the number normally present in humans, including 22 pairs of autosomes and the two sex chromosomes (XX or XY), which determine the sex of the organism. (
  • From these chromosomes and through DNA cells can construct an entire organism. (


  • In the language of the geneticist, trisomy refers to the presence of an additional chromosome that is homologous with one of the existing pairs so that that particular chromosome is present in triplicate. (
  • The term monosomy refers to the absence of one of a pair of homologous chromosomes. (


  • Either trisomy or monosomy involving the sex chromosomes yields relatively mild abnormalities. (


  • Most human traits and common diseases have a complex genetic makeup involving more than one gene. (
  • The maps currently represent more than 94% of the euchromatic (gene-containing) regions of these chromosomes in 176 contigs, and contain 96% of the chromosome-specific markers in the human gene map. (
  • This gene is intronless and is similar to a related gene located on chromosome 1. (
  • EST sequencing is a direct approach to human gene cataloging and has been responsible for the identification of thousands of genes in humans and other species. (
  • This gene is expressed at trace levels in mouse prenatal ovary and is barely detectable or absent from adult ovary, in human and in the mouse respectively. (


  • A condition known as mosaicism results from an error in the distribution of chromosomes between daughter cells during an early embryonic cell division, producing two and sometimes three populations of cells with different chromosome numbers in the same individual. (
  • This was surprising because previously the most diverged branches of the Y chromosome were found in traditional hunter-gatherer populations such as Pygmies and the click-speaking KhoeSan, who are considered to be the most diverged human populations living today. (


  • Hammer cautions against popular concepts of "mitochondrial Eve" or "Y chromosome Adam" that suggest all of humankind descended from exactly one pair of humans that lived at a certain point in human evolution. (
  • N-terminome analysis of the human mitochondrial proteome. (


  • The results are published in the American Journal of Human Genetics . (


  • When none of the genetic markers used to assign lineages to known Y chromosome groupings were found, the DNA sample was sent to Family Tree DNA for sequencing. (


  • The new divergent lineage, which was found in an individual who submitted his DNA to Family Tree DNA, a company specializing in DNA analysis to trace family roots, branched from the Y chromosome tree before the first appearance of anatomically modern humans in the fossil record. (
  • Our analysis indicates this lineage diverged from previously known Y chromosomes about 300,000 ago, a time when anatomically modern humans had not yet evolved," said Michael Hammer, an associate professor in the University of Arizona's department of ecology and evolutionary biology and a research scientist at the UA's Arizona Research Labs. (
  • It was not until more than 100,000 years later that anatomically modern humans appear in the fossil record. (
  • Granted, the oldest anatomically modern human remains have been found in East Africa 200-150 thousand years ago. (


  • Fernando Mendez, a postdoctoral researcher in Hammer's lab, led the effort to analyze the DNA sequence, which included more than 240,000 base pairs of the Y chromosome. (


  • Chromosomes are the carriers of genetic information. (


  • In study IV, as a part of the GenomEUtwin project, we performed genetic fine mapping of a linked locus for body height on the X-chromosome. (
  • Chromosomes are dark-staining, threadlike structures in the cell nucleus composed of DNA and chromatin that carry genetic information (definition after Nussbaum et al and Mueller and Young). (
  • Genetic information is packaged into a unit known as a chromosome. (
  • -University of Arizona geneticists have discovered the oldest known genetic branch of the human Y chromosome - the hereditary factor determining male sex. (
  • Unlike the other human chromosomes , the majority of the Y chromosome does not exchange genetic material with other chromosomes, which makes it simpler to trace ancestral relationships among contemporary lineages. (
  • Hammer said "the most striking feature of this research is that a consumer genetic testing company identified a lineage that didn't fit anywhere on the existing Y chromosome tree, even though the tree had been constructed based on perhaps a half-million individuals or more. (
  • Given the importance of Africa to studies of human origins and disease susceptibility, detailed characterization of African genetic diversity is needed. (


  • Toward a confocal subcellular atlas of the human proteome. (
  • Initial characterization of the human central proteome. (


  • the two most popular ways of cataloging human genes are sequencing expressed sequence tags (ESTs) and utilization of computational approaches. (
  • The DNA sequence of the human X chromosome. (


  • Formalized standard nomenclature for human chromosomes dates from 1960 and, since 1978, has been known as the International System for Human Cytogenetic Nomenclature (ISCN). (
  • Humans have X shaped chromosomes, e. coli has a circular chromosome known as a plasmid. (


  • About 300,000 years ago falls around the time the Neanderthals are believed to have split from the ancestral human lineage. (
  • We now know that there is no deep lineage of humans in modern east Africans. (


  • A chromosome is made up mostly of DNA and proteins that make up its structure. (


  • He added: "There has been a lot of hype with people trying to trace their Y chromosome to different tribes, but this individual from South Carolina can say he did it. (


  • An enzyme assisted RP-RPLC approach for in-depth analysis of human liver phosphoproteome. (


  • Cytogenetic disorders with visible chromosomal abnormalities are evidenced by either an abnormal number of chromosomes or some alteration in the structure of one or more chromosomes. (


  • By measuring the remaining gaps, we can assess chromosome length and coverage in sequenced clones. (


  • It is a very efficient and elegant system that oversees the life of all organisms from tiny cells to humans. (
  • DMP1 induced VE-cadherin and p27(Kip1) expression followed by cell cycle arrest in human umbilical vein endothelial cells (HUVEC) in a CD44-dependent manner. (


  • Through large database searches, his team eventually was able to find a similar chromosome in the Mbo, a population living in a tiny area of western Cameroon in sub-Saharan Africa. (


  • During cell division the material composing the chromosome is compactly coiled, making it visible with appropriate staining and permitting its movement in the cell with minimal entanglement. (
  • It is also possible to make a photomicrograph of a cell nucleus, cut it apart, and rearrange it so that the individual chromosomes are in order and labeled. (
  • POF1B localizes to desmosomes and regulates cell adhesion in human intestinal and keratinocyte cell lines. (


  • Identification of Mn2+-binding aspartates from alpha, beta, and gamma subunits of human NAD-dependent isocitrate dehydrogenase. (


  • Still, Hammer said, "It is likely that other divergent lineages will be found, whether in Africa or among African-Americans in the U.S. and that some of these may further increase the age of the Y chromosome tree. (


  • But as soon as they are linked together on a chromosome, selection creates correlations between nucleotides that are difficult to disentangle from each other. (
  • Instead, our results suggest that there are pockets of genetically isolated communities that together preserve a great deal of human diversity. (


  • Amelogenin sequences on the X and the Y chromosomes were also co-amplified to provide a correlation between embryo gender and deletion status. (


  • This pushes back the time the last common Y chromosome ancestor lived by almost 70 percent. (
  • If two Y chromosomes carry the same mutation, it is because they share a common paternal ancestor at some point in the past. (
  • The more mutations that differ between two Y chromosomes the farther back in time the common ancestor lived. (


  • The chromosomes can be stained by one of several techniques that produce a distinct pattern of light and dark bands along the chromosomes, and each chromosome can be recognized by its size and banding pattern. (
  • br>These range from a single component such as Viral genomes to several components as in the case of eukaryotic chromosomes. (