BIO VOCAB CH 14/15

Barr body

A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome.

multiplication rule 

A rule of probability stating that the probability of two or more independent events occurring together can be determined by multiplying their individual probabilities.

complete dominance 

The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable.

linked genes

Genes located close enough together on a chromosome that they tend to be inherited together.

polygenic inheritance

An additive effect of two or more genes on a single phenotypic character.

addition rule

A rule of probability stating that the probability of any one of two or more mutually exclusive events occurring can be determined by adding their individual probabilities.

monosomic 

Referring to a diploid cell that has only one copy of a particular chromosome instead of the normal two

carrier 

In genetics, an individual who is heterozygous at a given genetic locus for a recessively inherited disorder. The heterozygote is generally phenotypically normal for the disorder but can pass on the recessive allele to offspring.

nondisjunction

An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other

polyploidy 

A chromosomal alteration in which the organism possesses more than two complete chromosome sets. It is the result of an accident of cell division.