Chromosomes

CHROMOSOMES

Chromosome (chroma - colour; some - body)

  • A chromosome is a thread-like self-replicating genetic structure containing organized DNA molecule package found in the nucleus of the cell.
  • Clear and detaile decriptions of mitotic chromosomes in plants and animals were published by Strasburger in 1875 and by the German scientist Walter Flemming in 1879-1882.
  • Heinrich Wilhelm Gottfried Waldeyer coined the term chromosome in 1888.
  • Normally Chromosomes are of two types
    • Autosomes - Control characters other than sex characters or carry genes for somatic characters.
    • Sex chromosomes (Synonym: Gonosomes) - Chromosomes involved in sex determination.
      • Humans and most other mammals have two sex chromosomes X & Y, also called heterosome, odd chromosome, or idiosome.
      • Females have two X chromosomes in diploid cells; males have an X and a Y chromosome.
      • In birds the female (ZW) is hetero-gametic and male (ZZ) is homo-gametic.
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Last modified: Tuesday, 20 March 2012, 4:29 AM