Inheritance and Genetic Variation

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Genetics Noun

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[juh-net-iks]

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Genetics

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The scientific study of heredity and how characteristics are passed from parents to their offspring through genes.

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Example: The image shows how genes are located on chromosomes within a cell, explaining heredity.

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Trait Noun

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[trayt]

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Trait

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A specific, observable characteristic of an organism that is determined by its genes or the environment.

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Example: Different eye colors show traits as observable characteristics determined by genes.

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Gene Noun

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[jeen]

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Gene

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A fundamental unit of heredity transferred from a parent to offspring, which determines a specific characteristic.

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Example: A gene is a segment of DNA within a chromosome that determines specific traits.

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Allele Noun

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[uh-leel]

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Allele

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One of two or more alternative forms of a gene that are found at the same place on a chromosome.

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Example: The image shows alleles as different forms of a gene on chromosomes, explaining homozygous and heterozygous pairs.

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Genotype Noun

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[jee-noh-tipe]

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Genotype

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The specific combination of alleles an organism possesses for a particular genetic trait, often represented by letters.

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Example: The image shows different genotypes by displaying chromosomes with alleles labeled as 'A' and 'a'.

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Phenotype Noun

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[fee-noh-tipe]

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Phenotype

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The set of observable physical characteristics of an individual resulting from the interaction of its genotype with the environment.

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Example: The image shows how different genotypes in fruit flies lead to different wing types, illustrating phenotype.

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Dominant Allele Noun

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[dom-uh-nuhnt uh-leel]

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Dominant Allele

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An allele that produces the same phenotype whether its paired allele is identical or different, masking the other.

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Example: Dominant allele 'A' masks recessive 'a' in heterozygous pairs, showing phenotype.

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Recessive Allele Noun

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[ri-ses-iv uh-leel]

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Recessive Allele

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An allele that is only expressed in an organism's phenotype when two copies of it are present.

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Example: The image shows that recessive alleles (a) are expressed only when both alleles are recessive (aa).

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Homozygous Adjective

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[hoh-moh-zy-guhs]

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Homozygous

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A genetic condition where an individual has inherited two identical alleles for a particular gene from their parents.

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Example: Two identical alleles 'AA' or 'aa' on chromosomes show a homozygous genetic condition.

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Heterozygous Adjective

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[het-er-oh-zy-guhs]

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Heterozygous

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A genetic condition where an individual has inherited two different alleles for a particular gene from their parents.

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Example: The image shows heterozygous alleles (Aa) compared to homozygous alleles (AA, aa) using labeled chromosomes.