click below
click below
Normal Size Small Size show me how
Genetics Definitions
Exploring Creation with Biology - Module 8 (Genetics) Definitions
Question | Answer |
---|---|
True breeding | If an organism has a certain characteristic that is always passed on to all of its offspring, we say that this organism bred true with respect to that characteristic. |
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 | The observable expression of an organism's genes |
Homozygous genotype | A genotype in which both alleles are identical |
Heterozygous genotype | A genotype with two different alleles |
Dominant allele | An allele that will determine phenotype if even one is present in the genotype |
Recessive allele | An allele that will not determine the phenotype unless the genotype is homozygous with that allele |
Pedigree | A diagram that follows a particular species' phenotype through several generations |
Monohybrid cross | A cross between two individuals concentrating on only one definable trait |
Dihybrid cross | A cross between two individuals concentrating on two definable traits |
Autosomes | Chromosomes that do not determine the sex of the individual |
Sex chromosomes | Chromosomes that determine the sex of an individual |
Autosomal inheritance | Inheritance of a genetic trait not on a sex chromosome |
Genetic disease carrier | A person who is heterozygous in a recessive genetic disorder |
Sex-linked inheritance | Inheritance of a genetic trait located on the sex chromosomes |
Mutation | A radical change in one or more alleles |
Change in chromosome structure | A situation in which the chromosome loses or gains genes during meiosis |
Change in chromosome number | A 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 |
Mendel's First Principle of Genetics (updated terminology) | The traits of an organism are determined by its genes. |
Mendel's Second Principle of Genetics (updated terminology) | Each organism has two alleles that make up the genotype of a given trait. |
Mendel's Third Principle of Genetics (updated terminology) | In sexual reproduction, each parent contributes ONLY ONE of its alleles to the offspring. |
Mendel's Fourth Principle of Genetics (updated terminology) | In each genotype, there is a dominant allele. If it exists in an organism, the phenotype is determined by that allele. |