Mendelian Genetics Chap. #8 Flashcards
What is a Genotype?
A two-letter set that represents the alleles an organism possesses for a certain trait.
What is an Allele
One pair of genes that occupies the same position on a pair of homologous chromosomes.
What is a phenotype.
The observable expression of an organisms genes.
What is a homozygous genotype?
A genotype in which both alleles are identical.
What is True breeding?
If an organism has a certain characteristic that is always passed on to its offspring, we say to this organism has bred true with respect to that characteristic.
What is a Heterozygous genotype?
A genotype with two different alleles.
What is a recessive allele?
An allele that will not determine the phenotype unless the genotype is homozygous in that allele.
What is a dominant allele?
In allele that will determine the phenotype just one is present in the genotype.
What is a pedigree?
A diagram that follows a particular phenotype through several generations.
What are Autosomes?
Chromosomes that do not determine the sex of an individual.
What is a Genetic disease carrier?
A person who is heterozygous in a recessive genetic disorder.
Sex chromosomes
Chromosomes that determine the sex of an individual.
What it Autosomal inheritance?
Inheritance of a genetic trait not on a sex chromosome.
What is sex linked inheritance?
Inheritance of a genetic trait located in the sex chromosomes.
What is a mutation?
A radical chemical change in one or more alleles.
What is change in chromosome structure?
A situation in which a chromosome loses or gains genes during meiosis.
What is change 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.
What are the four principles of genetics?
- The traits of an organism are determined by its genes.
- Each organism has two alleles that make up the genotype for given traits.
- In sexual reproduction, each parent contributes only one of its alleles to its offspring.
- In each genotype, there is a dominant allele. If it exists in an organism, the trait determined by that dominant factor will be expressed.
What is a monohybrid cross?
A cross between two individuals, concentrating on only one definable trait.
What is a dihybrid cross?
A cross between two individuals, concentrating on to definable traits.
What is an antigen?
A protein that, when introduced in the blood, triggers the production of an antibody.
What is incomplete dominance?
When the alleles of a certain trait share dominance.
What is polygenetic inheritance?
The outcome of the interaction of several genes that determine one trait.
What is Epistasis?
The situation in which one set of alleles affects how another set of alleles is expressed.
What is pleiotropy?
When a single gene can affect multiple observable traits (multiple phenotypes).
