Inheritance and epigenetics Flashcards
What is cystic fibrosis?
inherited chronic disease that affects the lungs and digestive system by mutations to CFTR gene (cystic fibrosis transmembrane-conductance regulator) –> found on long arm of chromosome 7. most common mutation is F508 resulting in deletion of an amino acid (phenylalanine)
What are the symptoms of CF?
sinus problems, nose polyps, salty sweat, enlarged heart, frequent lung infections, gallstones
What inheritance pattern is cystic fibrosis?
autosomal recessive
What is Huntingdon’s disease?
Inherited, incurable, progressive neurodegenerative disease causing severe problems with motor skills, coordination, gait, mood and mental abilities
What inheritance pattern is Huntingdon’s?
Autosomal dominant. Only needs a single copy of mutant mHTT allele to cause the disease. 50% chance
What does genetic penetrance mean?
Extent to which acquisition of a mutated gene (allele) results in an associated phenotype.
What is Haemophilia A?
Caused by a lack of blood clotting factor VIII (the gene encoding human FVIII is called F8 and is carried on the X chromosome)
What are polygenic diseases?
Likely to result from the inheritance of multiple gene polymorphisms
What is heritability?
Single genotype can produce multiple phenotypes depending on the environment (E)
Different genotypes can produce the same phenotype depending on the environment
Heritability (h^2) = variation in genotype (G)/ Variation in Phenotype (P)
Why is heritability important?
Ranges from 0-1
If h^2 > 0.5 then genes are more important
If h^2 < 0.5 then the environment is more important
What is epigenetics?
study of stable changes in gene expression that do NOT involve changes (mutation) in DNA sequence eg. cancers, autoimmune disorders, obesity
What are the 4 filial generation?
F1= offspring of a genetically specified mating, first filial generation
F2= offspring of parents of contrasting genotypes, second filial generation
F3= offspring of two F1 individuals, third filial generation, an epigenetic change must be observed here
F4= etc.
What is independent assortment?
alleles of two or more different genes get sorted into gametes independently of one another. The allele a gamete receives for one gene does not influence the allele received for another gene.
