Introduction to Genetics

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Introduction to Genetics
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Chromosomes

• Chromosomes are made up of DNA wrapped around
  proteins.
• Each chromosome codes for several genes.
• Each Gene codes for a protein.

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Human genetics

• Each healthy person has 23 pairs of chromosomes.
  (46 total Diploid 2n)
• Each Pair codes for the same genes and are called
  Homologous Chromosomes
• You got 23 from your mom and 23 from your dad.

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Sperm and Egg are Haploid

• Sperm and eggs are haploid cells known as gametes
• Each Sperm has 23 Chromosomes
• Each Egg has 23 Chromosomes.
• 2 Gametes come together to form a zygote

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Homologous Chromosomes

• Homologous Chromosomes code for the same genes
• Different version of the same Gene are called
  alleles and will produce different proteins that
  may function differently.
• Some alleles are dominant (will be expressed no
  matter what)
• Some alleles are recessive (will only be
  expressed if you have two copies.)

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Hypothetical Example

• Dad is Homozygous Mom is Heterozygous

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• Visit a map of the Human Genome
• http//www.ncbi.nlm.nih.gov/science96/chr.cgi?1