Mendelian Inheritance and mitcohcondrial genetics Flashcards
What contributions lead to human disease?
Genetic and environmental
What are the classification of genetic disorders?
Single gene Multifactorial Chromosome Mitochondrial Somatic
How can gain or loss of gene function come about?
But mutations in DNA
What is a genotype?
A pair of alleles at a locus
What are some single gene disorders?
Autosomal Dominant
Autosomal Recessive
X-linked
What is autosomal dominance?
A dominant allele (mutation) will determine a
phenotype when only one copy is present
in the genome.
What are some autosomal dominant disoders?
FAP - Familial Adenomatous polyposis
Achondroplasia - Dwarfism
Marfan Syndrome
What are the features of autosomal dominant inheritance?
Affected individuals in every generation
Male and female equally likely to be affected
Inherited from one OR other affected parent
What phenotypes are generally encountered in autosomal dominant families?
Wild type and heterozygous mutant
Homozygous are usually very severe and often not seen
What type of disorder is cystic fibrosis?
Autosomal recessive
What are the features of cystic fibrosis?
Problems with: Lungs Pancreas Sweat glands Sometimes other organs
Encodes a transmembrane protein that transports chloride ions, Mutations disrupt this chloride conductance
Affects 1/2500 people
What are some other autosomal recessive disorders?
Primary Haemochromatosis Cystic fibrosis Sickle cell disease Phenylketonuria Ataxia Telangiectasia
What causes Ataxia Telangiectasia?
Biallelic mutation of ATM gene
Mutation can occur at any point in the gene and produces the same effect
What are autosomal recessive disorders?
A recessive allele has no effect on the organism’s
phenotype if only one copy of the allele is present
in the genome.
You could be carrying a mutation in a gene and be
totally unaware of this- case for carriers of recessive
Diseases
What are the features of autosomal recessive disorders?
Only seen in one generation
Both parents are normally carriers