AP Bio Chapter 15 Part 2 Flashcards
What does a + indicate
Wild type. Most flies have it, generally dominant
What is used to make a gene map
Percentage or cross over amount
Who came up with the term sex linkage and what does it mean
Morgen. Genes on sex chromosomes, some working together
Discovered in flies
In sexually reproducing organisms what determines sex
The dad
When Morgen’s cross of wing type and body color occurred, what were the expected results for linked genes
2 possibilities (1 to 1)
Gray, normal wings (b+bvg+vg)
Or
Black, vestigial wings (bbvgvg)
When Morgen’s cross of wing type and body color occurred, what were the expected results for unlinked genes
b+vg+ (GN) b+vg (GV) bvg+ (BN) bvg (BV) 4 possibilities --2 more New than the other cross 1:1:1:1 ratio
What does gene linkage refer to
Any genes in the same chromosome
Usually what type of genes will travel together during mitosis
Linked
What is the only way linked genes are separated
Crossing over events
As a result of linked genes only being able to be separated by crossing over, the higher the frequency of recombinant offspring for two genes
The greater the likelihood of there being a crossing over event between them
What results in a higher frequency of recombinant offspring for any two genes
A greater distance between the genes on a chromosome
What can the correlated information of distances of genes and higher recombinant offspring frequencies be used to do
Separate a “linkage map” of genes on a chromosome
Map units
Indicate distance between genes in a linkage map
No two genes can be more than how many map units and why
50
They’d look like they’re in different chromosomes
1 map unit =
1% chance of cross over (and recombinant offspring)
