14.1 - Human Heredity

• Karyotype: An organized picture of the human chromosomes

  • There are 46 human chromosomes or 23 pairs
  • The 23rd pair of chromosomes are the sex chromosomes and they determine your sex (X and Y chromosomes)
  • Female = XX
  • Male = XY
  • The other 44 chromosomes are called autosomes
  • Autosomes: autosomal chromosomes or body cell chromosomes
• Pedigrees: A map that shows how traits are passed on in a family

  • How to read a pedigree
  • squares = males
  • circles = females
  • shaded in = has trait
  • unshaded = doesn't have trait
• Single Allele Human Traits

  • Many human traits are controlled by a single pair of genes
  • Some are dominant traits, some are recessive, and some are incomplete or codominant
• • single genes are not the only things responsible for determining our characteristics
  • ex. polygenic traits, environmental factors & traits, multiple alleles