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Genetics

Field: Genetics

Sequence of Expressions

During gamete formation, the alleles for each gene segregate from each other so that each gamete carries only one allele for each gene.
When in the F1 offspring of two different animal races one sex is absent, rare, or sterile, that sex is the heterogametic sex.
Principle

Epistasis

The interaction of genes that are not alleles, in particular the suppression of the effect of one such gene by another.
Principle

Pleiotropy

The production by a single gene of two or more apparently unrelated phenotypic effects.
Hypothesis

Lyon Hypothesis

In cells with multiple X chromosomes, all but one are inactivated during mammalian embryogenesis (X-inactivation).
The 5' base on the anticodon of a tRNA can bind to the 3' base on the mRNA in a non-standard way, allowing a single tRNA to recognize multiple codons.
DNA sequences that are close together on a chromosome tend to be inherited together during the meiosis phase of sexual reproduction.
Principle

Gene Dosage

The amount of gene product in a cell is proportional to the number of copies of the gene present.
The determination of a particular characteristic, e.g. height or skin color, by many genes (polygenes), each having a small effect individually.