3.7 Genetics , populations , evolution and ecosystems (A- level only) Flashcards
what is a genotype?
The genetic constitution of an organism.
What is a phenotype?
The expression of the genes and its interaction with the environment.
What is a homozygous allele?
A pair of homologous chromosomes carrying the same alleles for a single gene.
What is a heterozygous allele?
A pair of homologous chromosomes carrying two different alleles for a single gene.
What is a recessive allele?
An allele only expressed if no dominant allele is present .
What is a dominant allele?
An allele that will always be expressed in the phenotype.
What is multiple alleles?
More than two alleles for a single gene.
What is sex - linkage ?
A gene whose locus is on the X chromosome.
What is autosomal linkage?
Genes that are located on the same chromosome ( not the sex - chromosomes).
What is epistasis?
When one gene modifies or masks the expression of a different gene at a different locus.
What is monohybrid inheritance?
Genetic inheritance cross of a characteristic determined by one gene.
What is dihybrid inheritance?
Genetic inheritance cross for a characteristic determined by two genes .
What is co dominance ?
Both alleles are equally dominant and expressed in the phenotype.
What is gene pool?
All the alleles of all genes within a population at one time.
What is population ?
All the individuals of one species in one area at one time.