Risk of ... inheritance Flashcards
What are some factors which are important in determining weather offspring will survive?
- Deleterious alleles
- Level of care
What is population genetics?
Change in alleles as a result of a change in selection pressures
What equations can be used to estimate the frequency of an allele in a population?
p +q =1
p^2 + 2pq + q^2 = 1
What are the conditions for the hardy-Weinberg equation to be true?
No mutations No migration No selection pressure Random mating large population Equal allele frequency in both sex
What does hardy-weinberg equation predict?
That the allele frequency will remain constant over time as long as the conditions are met.
What is assortative mating ?
Choosing a partner based on shared characteristics
What is consanguinity ?
Marriage between close blood relatives
What are two examples of non random mating?
Assortative and consanguinity
What is natural selection?
The gradual process by which biological traits become either more or less common in a population
What is positive selection?
Increase’s reproductive fitness and prevalence of adaptive traits giving a heterozygote advantage.
What is negative selection?
Reduction of reproductive fitness, decreases the prevalence of traits and gradual reduction of mutant alleles
Why is a large population important?
Because it can balance out fluctuations.
What are examples of times where change in population size has affected the allele frequency?
Statistical drift
Founder effect
Genetic drift
Bottleneck effect
What is genetic drift?
The random fluctuations in a trait from one generation to the next
What is statistical drift?
Is due to changes or random events.
What is the founder effect?
Change in trait frequency due to a small subset of the lager population stopping mating with the rest of the population
What is the bottleneck effect ?
Population size becomes drastically reduced for one or more generations
What does the body use as defence against cancer?
Oncogenes
Tumour suppressor genes
DNA damage-response genes
What is a pro-oncogene
A normal gene that codes for proteins to regulate cell growth and differentiation.
What is an oncogene?
A mutated proto-oncogene that can accelerate cell division
What is a tumour suppressor gene
Cells growth breaks. Mutations cause increase allow cell cycle rate to increase and apoptosis to decrease
What is a DNA damage-response gene?
Repair mechanisms for DNA
What happens if DNA damage-response genes fail?
Cause HNPCC and MSI
What is MMR
It corrects errors which occur. If it fails it causes MSI.
What are the three types of tumour?
Benign
Dysplastic
Malignant
What are the two ways in which genes can cause cancer?
Autosomal recessive syndromes - Both copies of the gene have an inherited mutation
De Novo mutations - Mutation in the germ cell of a parent
What genes can breast and ovarian cancer be linked to?
BRCA1 and BRCA2
Is Retinoblastoma heritable?
It can be, it also sometimes isent
What genes increase the risk of colon cancer ?
MLh1 and MSH2 and MSH6 etc HNPACC
