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Medical Dictionary Definitions A-Z List

Medical Dictionary Definitions A - Z - «Y»:

  1. Y (in chemistry) Y (in chemistry)
    Y (in chemistry): The symbol for the element yttrium, an ultrarare metal named after Ytterby in southern Sweden. Yttrium has been used in certain nuclear medicine scans....
  2. Y (in genetics) Y (in genetics)
    Y (in genetics): The Y chromosome, the sex chromosome found in normal males, together with an X chromosome....
  3. Y chromatin Y chromatin
    Y chromatin: A brilliantly fluorescent body seen under the microscope in cells containing a Y chromosome when the cells are stained with the dye quinacrine. Quinacrine lights up the Y chromosome more than other chromosomes. ...
  4. Y chromosome Y chromosome
    Y chromosome: The sex chromosome found together with an X chromosome in most normal males. 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 tes...
  5. Y chromosome infertility Y chromosome infertility
    Y chromosome infertility: Male infertility with oligozoospermia (a subnormal number of sperm) or azoospermia (the absence of sperm) caused by deletion or rearrangement of the long arm of the Y chromosome, as demonstrated by chromosome analysis or by molecular studies which may show microdeletions (...
  6. Y chromosome sex-determining region Y chromosome sex-determining region
    Y chromosome sex-determining region: See: Y sex-determining region....
  7. Y map Y map
    Y map: The array of genes on the Y chromosome. Once thought to be a genetic wasteland, the Y now is known to contain at least 20 genes. Some of these genes are unique to the Y including the Y-chromosome sex-determining region and male fitness genes that are active only in the testis and are though...
  8. Y sex-determining region Y sex-determining region
    Y sex-determining region: A region on the Y chromosome that determines the sex of the individual. This region goes by the symbol SRY (sex region Y). SRY is necessary and sufficient for male sex determination. It is the testis-determining factor. Mutations in SRY give rise to XY females with gonada...
  9. Y-linkage Y-linkage
    Y-linkage: The presence of a gene on the Y chromosome. Y-linkage is analogous to X-linkage (the presence of a gene on the X chromosome) in that it says a gene is on one of the sex chromosomes. It has often been said that little is known about Y-linkage. This is no longer true. As of the year 2000, a...
  10. Y-linked Y-linked
    Y-linked: A gene on the Y chromosome. A Y-linked gene is by necessity passed from father to son, since the Y chromosome can only be transmitted by a man to his male progeny. It has often been said that little is known about whether specific genes are or are not Y-linked. This is no longer true. As o...
  11. Y-linked gene Y-linked gene
    Y-linked gene: A gene on the Y chromosome. (Y-linkage is analogous to X-linkage (the presence of a gene on the X chromosome) in that it says a gene is on one of the sex chromosomes.) It has often been said that little is known about genes that may be Y-linked. This is no longer true. As of the year...
  12. Y-linked inheritance Y-linked inheritance
    Y-linked inheritance: Inheritance of genes on the Y chromosome. Since only males normally have a Y chromosome, Y-linked genes can only be transmitted from father to son. Y-linked inheritance is also called holandric inheritance. It has often been said that little is known about Y-linked inheritan...
  13. Y. pestis Y. pestis
    Y. pestis: Yersinia pestis, the bacteria that causes the bubonic plague which in the year 541 (as the Black Death) and later in the Middle Ages decimated Europe. The effects of the plague are described in the nursery rhyme "We all fall down." Y. pestis mainly infects rats and other rodents which...
  14. YAC YAC
    YAC:YAC stands for yeast artificial chromosome, a vector (carrier) created and used in the laboratory to clone pieces of DNA. A YAC is constructed from the telomeric, centromeric, and replication origin sequences needed for replication in yeast cells. (The telomere is the end of the chromosome; t...
  15. YAG laser surgery YAG laser surgery
    YAG laser surgery: The use of a YAG (yttrium-aluminum-garnet) laser to do surgery. One use for a YAG laser in surgery is to punch a hole in the iris to relieve increased pressure within the eye from acute angle-closure glaucoma. In this type of glaucoma, there is a sudden (acute) increase in press...