Gene Mapping Flashcards
Through what process do children inherit a ‘patchwork’ of parental chromosomes (never exact copies)?
Genetic recombination
What is independent assortment?
Independent assortment is a genetic term that refers to the variation of chromosomes, or genetic information, during sex cell division. This variation allows for genetic differentiation in offspring.
What happens if alleles are close together on homologous chromosomes?
There is little chance of recombination
What does recombination frequency range from?
zero to 0.5
What Greek letter signals the recombination frequency?
Theta
What happens if alleles are far apart on homologous chromosomes?
There is a high chance of recombination (can be as high as 50%)
What does the term ‘linkage’ refer to?
Tendency of alleles to transmit together
- More linkage = less independent assortment
- Larger recombination frequency (theta) will suggest the alleles are unlinked
How can linkage equilibrium be studied?
By studying the levels of different alleles in entire populations
- The levels of different genes found together in different people
- Can then see what genes travel together
What is the expected frequency of 2 genes found together?
0.45
If the frequency of 2 genes is found to be higher than 0.45 what is to be said about the haplotype?
The haplotype is in linkage disequilibrium
- If <0.45 the haplotype is in linkage equilibrium
If genes are closer together will genes display linkage equilibrium or disequilibrium?
Linkage disequilibrium
What does the likelihood of genes seperating (recombining) depend on?
Distance apart and size of population
What 2 factors affect linkage disequilibrium?
- Genetic disequilibrium
- Time alleles have been present in population
