Genetics - Patterns of Inheritance Flashcards
Principle of Segregation
Only on member of a gene pair is transmitted to offspring
Principle of independent assortment
Genes at different loci are transmitted independently of others
Genotype
Individual’s genetic constitution at a specific locus on a chromosomes (allele pairs)
Phenotype
Physical display of the genes
Karyotype
display of chromosomes ordered according to length
Types of genetic disorders
Nondisjunction (missing or extra chromosome), structural abnormalities, translocations
Single gene disorders
Disorders in which single genes are altered
Multifactorial disorders
Combination of genetic and environmental causes
Mitochondrial disorders
Alterations in mitochondrial chromosome
Autosomal dominant
If the gene is present, it will be dominant and be expressed
Non sex chromosome
autosome
How much of the DNA is on the X chromosome?
about 5%, more than 700 coding regions
Penetration
Degree to which a gene is expressed - example: someone who has the genotype for a disease may not always exhibit the disease
can be age dependent penetration - don’t show up until adulthood (I.e. Huntington’s, Alzheimer)
Expression
The severity of the disease can vary greatly
Environmental influences, modifier genes or different mutations can alter the expression
Repeat Expansion
Increasing severity in offspring - increased copies as genes are passed on
