Inheritance & Evolution Flashcards
Y2 (20 cards)
Define
Gene
A base sequence of DNA that codes for the amino acid sequence of a polypeptide which results in a characteristic
Define
Allele
One or more alternate versions of the same gene
Define
Genotype
The genetic constitution of an organism
The different alleles it has
Define
Phenotype
The espression of the genetic constitution & it’s interaction with the environment
Define
Gene locus
The position on a chromasone where a particular gene is found
Define
Dominant alleles of a gene
An allele whose characteristics appears in the phenotype when there is one copy
Define
Recessive alleles of a gene
An allele whose characteristics only appear in the phenotype when two copies are present
Define
Co-dominant alleles of a gene
An allele whose characteristics appear together with another allele in the phenotype as neither allele is recessive
Define
Multiple alleles
More than two alleles of a gene
Define
Diploid
A cell with two of each type of chromosome
homologous pairs of chromosomes
Define
Haploid
A cell with only one type of chromosone
Define
Heterozygous genotype
Two different alleles at the same gene locus on each of a pair of chromosomes
Define
Homozygous genotype
Two of the same alleles at the same gene locus on each of a pair of chromosomes
Define
Dihybrid inheritance
The inheritance of two characteristics which are controlled by different genes.
Define
Sex-linked characteristic
Alleles that code for the characteristic are located on the sex chromosomes.
X or Y chromosomes
Define
Autosomal chromosomes
autosome
A chromosome that is not a sex chromosome.
Define
Autosomal linkage
When two genes coding for different characteristics are located on the same chromosome and consequently are inherited together.
Define
Epistasis
When the alleles of one gene mask the expression of alleles on another gene.
Define
Dominant epistasis
Just one copy of the epistatic allele will block expression of the second gene
Define
Recessive epistasis
Two copies of the epistatic allele are required to block expression of the second gene
