Traits, Genes, and Alleles Notes

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Traits, Genes, and Alleles Notes

• 3a. Predict the probable outcome of phenotypes
  in a genetic cross from the genotypes of the
  parents and mode of inheritance (autosomal or
  x-linked, dominant or recessive).

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Objectives

• Explain how there can be many versions of one
  gene.
• Describe how genes influence the development of
  traits.

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Vocabulary

• Gene
• Allele
• Homozygous
• Heterozygous
• Genotype
• Phenotype
• Dominant
• Recessive

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• The same gene can have many versions.

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Gene

• Specific region of DNA that codes for a
  particular protein.

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Allele

• Alternative forms of a gene that occur at a
  specific place on a chromosome.

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Homozygous

• Having two of the same alleles for a given gene
  on homologous chromosomes.

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Heterozygous

• Having two different alleles for a given gene on
  homologous chromosomes.

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• Genes influence the development of traits.

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Genotype

• Genetic makeup of a specific set of genes.

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Phenotype

• Physical characteristics, or traits, of an
  individual organism.

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Dominant

• Allele that is expressed when two different
  alleles are present in an organisms genotype.

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Recessive

• Allele that is not expressed unless two copies
  are present in an organisms genotype.