Session 7: Phenotype, Genotyope And Inheritence Flashcards
Define heterozygous.
Two alleles of a gene are different
Define homozygous.
Two alleles of a gene are the same
Define hemizygous
One copy of a gene presently only (on the X chromosome of males)
Define co-dominance.
Neither allele is dominant over the other
Describe autosomal recessive inheritance.
- Males and females affected equally
- disease appears to ‘come out of nowhere’ as it can skip generations
Give an example of an autosomal crisis even inherited condition.
CF
Describe autosomal dominant inheritance.
- Males and females affected equally
- every individual has at least one affected parent I.e. The disease cannot skip generations
Give an example of an autosomal dominant disease.
Huntingtons
Describe X-linked recessive inheritance.
- more males affected than females
- mothers of affected females must be carriers and fathers must be affected
Give an example of an X-linked recessive disease.
Haemophilia A
Describe X-linked dominant inheritance.
- affected males cannot give trait to son but will give it to all of their daughters
Describe mitochondrial inheritance.
- passed on by mother
- all children affected however only daughters pass it on
Define polygenic.
More than one gene is involved in producing the phenotype.
Give an example of a polygenic inherited condition.
Albinism
