In sporadic cases of retinoblastoma, only two gene mutations are thought to be necessary in the same cell for a tumor to develop. This happens when an organism inherits a mutant allele and a wild-type allele from the parents. When the wild-type allele is mutated, resulting in tumorigenesis, this process is called, ________.Group of answer choicesrecombinationattenuationgain of heterozygosityloss of heterozygosity

Neoplasia:Group of answer choicesis usually a three-stage processonly occurs as a result of mutations occurring in the individualusually involves a single mutationusually involves a single geneNext

Which mechanism is least likely to inactivate a tumor-suppressor gene?Group of answer choicesmutationchemical modificationloss of heterozygositygene duplication

hich of the following describes a gene?*Trait of an individualCell of an organismCarrier of hereditary traitsFactor that causes mutation

It occurs when a single gene has more than one phenotypic expression.Group of answer choicescodominancepolygenicmultifactorialpleiotropyepistasisNext

The mutations that cause genetic variation occur in the