7-Introduction to human genetics and single gene disorders Flashcards
What is the locus of a gene?
The location of the gene on a particular chromosome
What is an allele?
The particular form of the gene inherited from your mother or father
What does dominant mean?
One copy of the gene causes disease
What does recessive mean?
Both copies require the gene to occur
What is meant by homozyogous?
Identical alleles
What is meant by heterozygous?
Different alleles
What is meant by the genotype?
The genetic make-up of the individual
What is meant by phenotype?
The physical expression of the genotype
What is meant by autosomal dominant?
Gene at one allele determines the phenotype
What is the 6 things that identify the autosomal dominant inheritance?
50% of offspring affected male=female Transmission can be of any combination Does not skip generation De novo mutations Penetrance can be < 100%
What is haplo-insufficiency?
You need both copies of the gene to be expressed
What is dominant negative?
Mutant protein acquires new deleterious function
What is meant by autosomal recessive?
Genes at both alleles determines the phenotype
What are the 4 things that identify autosomal recessive inheritance?
25% offspring affected
male=female
50% offspring carriers
Consanguinity
What are the three factors that identify the X- linked recessive?
50% male offspring affected
50% female offspring carriers
mother - son transmission
