Human+Genetics

 ·   Chromosomes A chromosome is a long, rod-shaped structure composed of DNA and proteins. The single DNA molecule contains many genes · A gene is a region of DNA that controls hereditary characteristics ·   1 chromosome = 1 strand of DNA o  Chromosome numbers ·  Each species has a specific number of chromosomes in each cell (Except sex cells) ·  Humans have 46 chromosomes o  Types of chromosomes ·  Sex chromosomes ·  Chromosomes that determine the sex of an organism ·  In humans o  Normal Female- XX    o   Normal Male - XY    §    Pair 23 ·  Autosomes · All chromosomes in an organism that aren’t sex cells  §   Pairs 1-22 ·  Organisms receive one copy of each autosome from each parent ·    Two copies are called homologous chromosomes
 * Pair of homologous chromosomes  ||
 * This is an example of a pedigree. The shaded areas are affected offspring. A pedigree is like a family tree. ||
 * Sister Chromatids ||

·  Pedigree ·  Used by genealogists ·  Shows all possible phenotypes for an individual ·   Genetic Disorders o  Mutations ·  Can occur in an entire chromosome or a single nucleotide ·  Fatal mutations ·  Mutations that occur and the child will most likely die before birth.  ·   Single allele mutations ·  Achondroplasia ·  Cataracts ·  Polydactyly ·  Albinism ·  Sickle cell anemia  ·   Multifactoral ·  Hard to treat ·  Hard to research  ·   Chromosomal Abnormality ·  Pieces of the chromosome are either: deleted, duplicated, inserted, or translocated. o  Example: down syndrome.