Medelian Genetics Flashcards
What is the law of independent assortment?
The alleles of a gene for one trait segregate independently from the alleles of a gene for another trait if the genes are located on separate chromosomes.
Distinguish between codominace and incomplete dominance?
In codominace both phenotype so are displayed whereas in incomplete dominance a blended phenotype is displayed
What is pleiotropy?
This is when one gene affects an organism in multiple ways.
What is epistasis?
Two separate genes control a trait but one gene can mask the expression of the other gene. The gene that masks is epistasic to the gene it masks.
What is polygenic inheritance?
These are traits that vary along a continuum and when multiple genes affect a single trait
What is the law of segregation?
During the formation of gametes the two alleles are separated
What are common sex linked conditions?
Color blindness, hemophilia and muscular dystrophy
What is x-inactivation?
In all females an X chromosome is inactivated in every somatic cell. This creates a genetic mosaic where some cells have one x inactivated and other cells have the other x inactivated. This inactivated x turns into a dark spot of chromatin and is called a Barr Body.
Name some dominant mutation conditions.
Huntingtons disease,
What is Down syndrome, Turner syndrome, and kleinfelters syndrome?
Down syndrome- extra chromosome 21
Turners- xo, missing an X chromosome still female
Kleinfelters- xxy , male but sterile
What are 4 types of chromosomal aberrations?
Deletion- when a fragment lacking a centromere is lost during cell division
Inversion - a chromosomal fragment reattaches in the inverse direction
Translocation- when a chromosome fragment is attached to a non homologous chromosome
Polyploidy- when a cell has an extra set of chromosomes
Is nondisjunction more dangerous in meiosis 1 or 2?
It is more dangerous for nondisjunction in meiosis 1 because two have n+1 and two have n-1. In nondisjunction in meiosis 2, one has n+1, one has n-1, and two have n.
