recessive allele

the version of a gene (see allele) whose effects are manifest only if it is carried on both members of a homologous pair of chromosomes. Hence, the trait determined by a recessive allele (the recessive trait) is apparent only in the absence of another version of that same gene (the dominant allele). The term autosomal recessive is used to describe patterns of inheritance in which characteristics are conveyed by recessive alleles. For example, Tay–Sachs disease is an autosomal recessive disorder.

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Psychology term of the day

November 18th 2024

contrast effect

1. the perception of an intensified or heightened difference between two stimuli or sensations when they are juxtaposed or when one immediately follows the other. Examples include the effect produced when a trombone follows a violin or when bright yellow and red are viewed simultaneously.

2. in psychology experiments, an effect in which participants’ judgments shift away from an anchor after it is introduced. Compare assimilation effect.