Flashcards- Ch 14 Notes Part I Mendel

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Trait

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Some aspect of an organism that can be described or measured. Example: eye color, flower color.

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Gene

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Discrete unit of hereditary information or a specific sequence of DNA that codes for a protein.

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Allele

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Alternative versions of a gene. Example: red vs. white flowers; A, B, or O blood group instructions.

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Genotype

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An organism's actual genetic makeup; their set of alleles. Examples include BB, Bb, bb

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Phenotype

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Physical or physiological characteristics of an organism determined by the genotype. Examples include normal Hb or sickle cell Hb, blue eyes, brown feathers, and 5 fingers on a hand.

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Homozygous: an individual that inherits 2 identical alleles for a gene

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Example: BB or bb

Also called true-breeding or pure-bred

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Heterozygous: an individual that inherits 2 different alleles for a gene

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Example: Bb; Also called "hybrid"

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Dominant allele

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an allele that is fully expressed in the phenotype of a heterozygote

Example: B = Black and b = white; BB or Bb results in black coloration. Dominant does NOT mean the allele occurs more frequently or is better!

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Recessive allele

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an allele that is not observed in the phenotype of a heterozygote

Need to inherit 2 recessive alleles to see that phenotype. Example: will only see white coloration when inherit bb

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Gregor Mendel

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Gregor Mendel (1800s); an Austrian monk, applied mathematics to his study of genetics.