Meiosis/Genetics

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Meiosis/Genetics

• Topic 4

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Stages of Meiosis
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Meiosis Stage 2
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Genes and Chromosomes

• Terminology
• Genotype genetic constitution of a gene/org
• Phenotype physical expression of a gene
• Dominant allele form of the gene that is
  expressed even when only 1 is present
• Recessive allele form of the gene that is only
  expressed when both alleles are recessive

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Terminology contd

• Codominant allele when two two forms of a gene
  are both expressed when paired together
• Locus the location of a gene/allele on a
  chromosome
• Homozygous when both alleles of a gene are the
  same (ex. aa, AA)
• Heterozygous when both alleles of a gene

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Terminology contd

• Carrier an individual of heterozygous make-up
  that carriers, and therefore can pass on, a
  disease causing allele but doesnt express that
  trait
• Test cross when an individual of known
  phenotype but unknown genotype (AA or Aa) is
  crossed with a homozygous recessive individual in
  order to determine its genetic make-up.

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Mendelian Genetics Monohybrid Cross
Classical Punett's Square is a way to determine
ways traits can segregate
parental P cross
F1 cross
testcross mating F1 generation to the parental
(usually recessive) strain

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Some genes have more than two alleles- Blood
surface antigens
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Blood type also and ex. Of Codominance
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Sex-linkage basics
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Sex-linkage notes page
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Pedigree basics
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Pedigrees and pedigree analysis
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Sex-linked Pedigree