Genetics, Populations, Evolution And Ecosystems Flashcards
What is the gene pool?
All of the alleles of all of the genes within a population at one time
What is allele frequency?
The proportion of an allele within a gene pool
What does hardy Weinberg assume?
That there will be no change in allele frequency from one generation to the next
What are the multiple assumptions of the hardy Weinberg principle?
There is no migration
There is no mutation creating new alleles
There is no selection of favouring a specific allele
Mating is random
Population is large
What are the equations in the Hari Weinberg principle?
p^2 + 2pq + q^2 =1 (when talking about genotypes)
p + q = 1 (when talking about allele frequency)
In the hardy Weinberg principle, what does p and q mean?
p is the frequency of dominant alleles
q is the frequency of recessive alleles
When dealing with a hardy Weinberg question what should you do with the percentage?
Turn it into a decimal (divide by 100)
If in a hardy Weinberg question, you need to work out 2pq, should you take away p squared and q squared from one or times two by p and q?
Always 2 x p x q
What is epistasis?
When one gene affects or masks, the expression of another
What are dihybrid crosses?
A genetic cross where two genes are considered at the same time
When a homozygous dominant parent is paired with a homozygous recessive parent? What will the offspring always be?
Heterozygous
In a dihybrid cross if both parents are heterozygous, what will always be the ratio for offspring phenotype?
9:3:3:1
What are the exceptions to the rule of the 9:3:3:1 ratio?
If there is autosomal linkage involved or crossing over happens in meiosis
What does crossing over in meiosis result in?
New combinations of alleles
What is autosomal linkage?
When two alleles are located on the same chromosome (not on the Y or X)
What does autosomal linkage mean in terms of inheritance?
It means that the genes on the the same chromosome will be inherited together
What does the 9:3:3:1 ratio become when the genes are autosomally linked?
3:1
What is the only thing that can effect autosomal linkage?
Crossing over of alleles
Where do sex linked traits come from?
Alleles on the sex chromosomes
