Pedigrees

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Pedigree Noun

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[ped-i-gree]

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Pedigree

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A genetic family tree or chart that shows how a specific trait is passed down through generations.

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Example: This chart uses symbols to track a specific trait through three generations of a family, showing parents, children, and who is affected.

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Phenotype Noun

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[fee-noh-tiep]

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Phenotype

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The set of observable physical characteristics or traits of an organism, resulting from its genetic makeup and environment.

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Example: This pedigree chart shows phenotype, the observable trait, by using colored shapes. Brown or blue eye color is the phenotype determined by an individual's genes.

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Genotype Noun

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[jee-noh-tiep]

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Genotype

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The genetic constitution of an individual organism, representing its specific combination of alleles for a particular gene.

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Example: This diagram shows the genotype, or the combination of alleles on chromosomes. An individual can be homozygous (two identical alleles, AA or aa) or heterozygous (two different alleles, Aa).

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Hereditary Adjective

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[huh-red-i-ter-ee]

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Hereditary

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Relating to the passing of genetic traits from parents to their offspring through genes.

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Example: This pedigree chart shows how hereditary traits, like eye color, are passed down through a family, with recessive traits like blue eyes (bb) sometimes skipping a generation.

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Trait Noun

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[trayt]

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Trait

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A specific characteristic of an individual organism that is determined by its genes or environment.

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Example: This Punnett square shows how the trait for eye color is inherited. Combining gene variants from parents determines if the offspring will have brown or blue eyes.

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Carrier Noun

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[kar-ee-er]

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Carrier

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An individual who is heterozygous for a recessive trait, carrying the allele without expressing the associated phenotype.

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Example: This diagram shows two carrier parents, each having one working gene and one faulty gene, and the possible genetic outcomes for their children.

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Heterozygous Adjective

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[het-er-oh-zy-gus]

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Heterozygous

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Having two different alleles for a particular gene, one inherited from each parent.

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Example: This diagram shows that a heterozygous individual has two different versions (alleles) of a gene, represented by 'B' and 'b', on a pair of chromosomes.

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Homozygous Adjective

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[hoh-moh-zy-gus]

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Homozygous

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Having two identical alleles for a particular gene, one inherited from each parent.

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Example: This diagram shows homologous chromosomes with two identical alleles (AA or aa), which is the definition of a homozygous genotype.

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Autosomal Adjective

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[aw-toh-soh-muhl]

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Autosomal

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Relating to a gene located on any chromosome that is not a sex chromosome.

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Example: This pedigree chart shows how a trait on an autosome (a non-sex chromosome) is passed from parents to children, affecting both males and females.

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Sex-linked Adjective

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[seks-lingkt]

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Sex-linked

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Relating to a trait or gene that is located on one of the sex chromosomes, either X or Y.

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Example: This pedigree chart shows how a sex-linked trait is passed down through generations, with carrier females passing the trait to some of their sons.