Gregor Mendel

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Gregor Mendel

• 2007

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• GENETICS
• Study of heredity (inheritance of traits)
• Trait specific characteristic (height, eye
  color) that varies from one individual to
  another.
• Traits are passed through the gamete cells formed
  in meiosis.

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• GREGOR MENDEL
• Father of Genetics
• Developed basic principles of genetics studying
  garden peas.
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• PRINCIPLES OF GENETICS
• 1. Traits are controlled by genes on
  chromosomes.
• Traits are represented with letters
• Ex F freckles, D dimples
• 2. Genes exist in different forms called
  alleles.
• Ex Gene that controls the number of digits a
  person has.
• Allele 1 six-digits
• Allele 2 five digits
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• Variations in alleles are due to different DNA
  sequences in the gene.
• Many alleles (variations of a gene) may exist in
  a population.
• An individual has two alleles for each gene, one
  inherited from each parent.
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• 3. Alleles can be dominant or recessive
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• PRINCIPLE OF DOMINANCE the dominant allele masks
  the recessive allele when both are present.
• The recessive trait will only be seen if a person
  has two recessive alleles
• Dominant allele uppercase letter and recessive
  allele lowercase letter
• Ex Dimples is dominant (DD or Dd), no dimples is
  recessive (dd).
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• NOTE MUST USE THE SAME LETTER OF THE ALPHABET
  AND VARY UPPER AND LOWERCASE TO SHOW DOMINANT AND
  RECESSIVE ALLELES!
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• GENOTYPE combination of alleles a person has for
  a particular trait.
• Homozygous alleles are the same (Ex FF or ff)
• Heterozygous alleles are different (Ex Ff)
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• PHENOTYPE physical characteristics that result
  from an individuals genotype. (Ex the
  individual has freckles

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• What would be the genotype of someone homozygous
  for faulty dentin?
• DD
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• 2. What would be the genotype of someone with
  normal dentin?
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• dd

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• 3. What would be the phenotype of someone with a
  Dd genotype?
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• Faulty Dentin