Inheritance Flashcards
Meaning of multiple alleles
More than 2 alleles
But only 2 can be present
How do you draw co-dominance in the diagram
Use superscript on a letter
ie small letters floating in the air next to the big letter
What is the dominance hierarchy
sometimes if more than 3 alleles they’re arranged in a hierarchy
Dominant above, recessive below
In a pedigree chart, what does a square represent?
Male
In a pedigree chart, what does a circle represent
Female
In a pedigree chart, what does shading represent?
Sufferer
In a pedigree chart, what does half shading or a dot represent?
Carrier
Meaning of co-dominance
Both alleles are equally dominant
What is the hardy-Weinberg equation used for?
Predicting the number of dominant and recessive alleles in a population
What is the hardy-Weinberg equation?
P2 + 2pq + q2
What does allelic frequency mean?
The number of times an allele occurs in a gene pool
what is a gene pool
All the alleles of all the genes of all the individuals in a population at any one time
In the hardy-Weinberg equations what does P2 represent
Homozygous dominant
In the hardy-Weinberg equation what does q2 represent?
Homozygous recessive
In the hardy-Weinberg equation what does 2pq mean?
Heterozygous
When can’t you use the hardy-Weinberg equation?
If small population If mutations arise If individuals are mating randomly If natural selection happening If gene flow between populations from migration or transfer of gamets
What does it mean if a population is said to be in hardy-Weinberg equilibrium
A population’s genotype and allele frequencies will remain unchanged over successive generations
How do you work out the genes in a population using the hardy-Weinberg equation?
Get q2 Square root it to find q Do p = 1 - q Do p2 by doing p xs p Put back into equation
What is the process of speciation
Mutation creates variation Geographical isolation Breeding between them prevented Selections pressures different Advantage Survive and reproduce Alleles frequency increase or decrease Speciation
What happens to two groups of animals if speciation occurs
They can no longer produce fertile offspring if they breed
What is directional selection
Selections favours individuals that vary in one direction from the mean of the population
What is stabilising selection
Selection favours average individuals
What happens if directional selections occurs
Characteristics of populations changes, new mean created
What happens if stabilising selection occurs
Characteristics of population is preserved
