Human Genetics 1 Flashcards
How has medicine shifted in the past thirty years?
The chief cause of death has gone from infectious diseases to chronic constitutional or hereditary diseases
What is cytogenetics?
Study of chromosome structure and identification of microscopically visible abnormalities
What is molecular genetics?
The study of the structure and function of genes
What is biochemical genetics?
How genetic defects disrupt normal metabolism/cell control mechanisms
What is population genetics?
The study of how allele frequencies change in a population.
What is clinical genetics?
Diagnosis/detection of inherited disorders; treatment; risk assessment; genetic counseling; and pharmacogenomics
What is Pharmacogenmoics?
The study of the role of inherited and acquired genetic variation in drug response
What is the Law of segregation?
Each individual possesses two genes for a particular characteristic, only one of which can be transmitted at any one time
Only deals with one trait
What codominance?
alleles are expressed independently of the presence of each other
E.g. A and B alleles in blood
What is the law of independent assortment?
Members of different pairs of alleles are assorted independently into gametes, and subsequent pairing of male and female gametes is random.
Talks about two or more traits
What are the five exceptions to the law of independent assortment?
Epistasis
Linkage
Genomic imprinting
Mitochondrial Inheritance
Germline mosaicism
What is epistasis?
The situation in which one gene masks the expression of another.
E.g. blue eyes
What is Gene linkage?
The greater association in inheritance of two or more nonallelic genes than is to be expected from independent assortment
What is genomic imprinting?
the phenomenon whereby the degree to which a gene expresses itself depends upon the parent transmitting it
What is mitochondrial inheritance?
The inheritance of a trait encoded in the mitochondrial genome
What is germinal mosaicism?
when an individual is composed of two or more cell lines in their germ cell population, where these cell lines are of different genetic or chromosomal constitution
What are the four main types of genetic diseases?
Single-gene disorders
Chromosome disorders
Multifactorial disorders
Somatic cell genetic defects
Describe Single gene defects
Stem from polymorphisms or mutations in one gene, have modes of inheritance.
E.g. cystic fibrosis, sickle cell
Rare, affect 2% of the population sometime during lifetime
Describe chromosome disorders
Defect is dues to an excess or deficiency of the genes contained in whole chromosomes or chromosome segments.
E.g. Down or Patau syndrome
Describe multifactorial inheritance disorders
inheritance by a combination of genetic factors and in some cases also non-genetic factors, each with only a relatively small effect.
E.g. Alzheimer, COPD, diabetes
Recur within families but they do not show any particular pedigree pattern
