Genetics: Inheritance
Meiosis: Summary
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Diploid Cells (2n): Cells with two sets of chromosomes, (aka “homologous
chromosomes”)
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One set of chromosomes from each parent
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normal body cells
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Produced by mitosis
Haploid Cells (n): Cells with one set of chromosomes
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Gametes or sex cells
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Produced by meiosis
Meiosis: 2 rounds of cell division that produce cells with HALF the number of
chromosomes
Mitosis vs. Meiosis
Some Definitions….
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Genetics: The scientific study of heredity.
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Trait: A specific characteristic of an individual. (For example??)
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Gene:
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Sequence of DNA that codes for a protein (and, therefore, a trait)
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Passed down from parent to offspring
Allele: Different possible forms of a gene (one from each parent)
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Homozygous: 2 of the same allele for the same gene
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Heterozygous: different alleles for the same gene
Principle of Dominance
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Definition: Some alleles are dominant and others are recessive
Which is the dominant allele for eye color,
and which is the recessive?
Which are the dominant alleles and which are the
recessive? How do you know?
Genotype vs. Phenotype
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Genotype: the genetic makeup (i.e. combination of alleles for each particular
gene)
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Phenotype: the physical traits exhibited by an organism (observable)
Can we PREDICT which trait(s) will be
inherited??
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Probability: Definition??
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Punnett Squares
Meiosis: How do we get genetic diversity?
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Crossing Over
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Segregation
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Fertilization
Recessive Genetic Disorders
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What common trends might genetic disorders have? (Think about what DNA
and genes CODE for!)
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Examples: Cystic Fibrosis, Tay Sachs Disease, Albinism
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If a genetic disorder is RECESSIVE, what does that mean?
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How might completely healthy parents have a child with a recessive genetic
disorder?