3.5 Chromosomal Segregation and Mapping Flashcards
What did Walter Sutton discover in the 1900s?
that an organism must contain more unit factors than chromosomes
Where can genes be mapped to?
a specific location on a chromosome
What does it mean for genes to be linked?
genes that are located on the same chromosome
What is Mendel’s theory of independent assortment only true for?
chromosomes, NOT genes
What is recombination?
when tetrads interchange parts of their chromosomes during meiosis I
What is the frequency of crossing over of any two loci proportional to?
the distance between them on a chromosome
What have chromosome maps enabled scientists to do?
understand the makeup of genomes of human and other organisms
Which genes can independently assort?
ones that are located on DIFFERENT chromosomes
What is complete linkage?
alleles are so close they will not undergo recombination
What does complete linkage result in?
parental gametes in equal proportion
What is a genetics rule in relation to recombination and crossing over?
the percentage of tetrads involved in an exchange between two genes is twice as great as the percentage of Recombinant gametes produced
What are DCOs?
double cross overs
When do DCOs occur?
when the arms of the chromatids twist more than once
What do you need in order to study double exchanges?
three separates genes
What can you use to determine how often a double crossover will occur?
law of probabilities
