Question | Answer |
True breeding | When a certain characteristic is always passed on to offspring |
Allele | One of a pair of genes that occupies the same position on homologous chromosomes |
Genotype | Two-letter set that represents the alleles an organism possesses for a certain trait |
Phenotype | Observable expression of an organism's genes |
Homozygous genotype | Genotype in which both alleles are identical |
Heterozygous genotype | Genotype with two different alleles |
Dominant allele | Allele that will determine phenotype if just one is present in the genotype |
Recessive allele | Allele that will not determine the phenotype unless the genotype is homozygous in that allele |
Mendel's Principles of Genetics #1 | The traits of an organism are determined by its genes. |
Mendel's Principles of Genetics #2 | Each organism has two alleles that make up the genotype for a given trait. |
Mendel's Principles of Genetics #3 | In sexual reproduction, each parent contributes only one of its alleles to the offspring. |
Mendel's Principles of Genetics #4 | In each genotype there is a dominant allele. If it exists in an organism the phenotype is determined by that allele. |
Pedigree | Diagram that follows a particular phenotype through several generations. |
Monohybrid cross | Cross between two individuals, concentrating on only one definable trait |
Dihybrid cross | Cross between two individuals, concentrating on two definable traits |
Autosomes | Chromosomes that do not determine the sex of an individual |
Sex chromosomes | Chromosomes that determine the sex of an individual |
Antigen | Protein that triggers the production of an antibody when introduced in the blood |
Autosomal inheritance | Inheritance of a genetic trait not on a sex chromosome |
Genetic disease carrier | Person who is heterozygous in a recessive genetic disorder |
Sex-linked inheritance | Inheritance of a genetic trait located on the sex chromosomes |
Mutation | Radical chemical change in one or more alleles |
Change in chromosome structure | Situation in which a chromosome loses or gains genes during meiosis |
Change in chromosome number | Situation in which abnormal cellular events in meiosis lead to either none of a particular chromosome in the gamete or more than one chromosome in the gamete |