Inheritance Flashcards
What is a gene?
A sequence of bases on a DNA molecule that codes for a protein resulting in characteristics
What is an allele?
A different version of a gene
What is a genotype?
The genetic constitution of an organism (BB or Bb or bb)
What is a phenotype?
The expression of its genetic constitution and its interaction with the environment
What is a dominant allele?
An allele whose characteristics appears in the phenotype even if there’s one copy (capital letter)
What is a recessive allele?
An allele whose characteristics only appear in the phenotype if there are two copies (lowercase letter)
Define homozygote
An organism that carries two copies of the same allele
Define hetozygote
An organisms that carries two different alleles
What genetic diseases are be caused by recessive alleles?
Cystic fibrosis
Sickle cell anaemia
Phenylketonuria
What genetic diseases are caused by dominant alleles?
Huntingdon’s disease
Dwarfism
Type 1 neurofibromatosis
What is monohybrid inheritance?
Inheritance of a single gene
What is codominance?
When both alleles are expressed in the phenotypes. Neither one is recessive. It occurs when 2 inherited alleles both show dominance.
What is dihybrid inheritance?
Inheritance of two different genes
What is the phenotypic ration for a monohybrid cross with a homozygous dominant and a homozygous recessive?
3:1 (all heterozygous offspring)
What is the phenotypic ration for a dihybrid cross with a homozygous dominant and a homozygous recessive?
9:3:3:1 (all heterozygous offspring)
