BSC exam 4
Terms
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- hardy-weinberg law
- predicts the proportions of the various genotypes expected within random mating proportions
- negitive eugenics
- decreasing the frequency of harmful alleles -->illegal for someone to have a severe genetic disease to reproduce
- natural selection
- genotypes produce at different rates
- Genetic counselors
- use tables of recurrance and collecting of fetal cells --> amneocentisis, choviorionic villi sampling, fetal cell sorting
- eugenics
- artificial improvement of the human gene pool.
- positive eugenetics
- -increase the frequency of good alleles -example: male medical students donating sperm
- quantitative traits
- are affected by many genes
- quantitative genetics
- study of traits that have complex inheritance
- typical quantitative trait locus
- exibits additivity
- monozygotic twins
- identitical
- dizygotic twins
- fraternal may or may not be the same sex
- concordant
- twins exhibiting the same phenotype (physical characteristic) -example: if two twins were examined and neither ever had measles
- discordant
- twins displaying different phenotypes (physical characteristics)
- genetic drift
- random chance fluctuations in allele frequencies (in p and q) -important in small populations -1 of 4 evolutionary forces
- phenotypes are composed of...
- genotypes and environment
- heritability
- the proportion of the ovserved variation for some trait due to genetic differences among individuals
- how do you collect fetal cells from a pregnant woman?
- chroronic villus sampling, amniocentesis, fetal cell sorting
- recurrance risk
- if a couple has a child with a severe genetic disease... its the risk that the second child would have the sme genetic disease
- mutation
- -recurrent mutation (A-->a) -p(r) slowly decreases and q(a) slowly increses -harmfl alleles are still found in the human gene pool -reduce risk & increse risk the frequency
- assortive mating
- searching for mate with same phenotype
- artificial selection
- in plant and animal breeding
- inbreed mating
- mating with someone who has similar genotypes as themselves (a relative) -BAD --> DdxDd results in DD Dd Dd dd -1/4 chance dd=BAD
- heterozygoute advantage
- AA-0 Aa-1 aa-0 reason for harmful alleles in a population -involves a single eveloutionary fource and the greater fitness associated with the heterozygotes
- polygenic trait
- affected by many genes
- random mating
- pandemictic (panmixia) -choose mate with no regard to genotype of phenotype -in regard to ABO blood group, most human populations use this mating (basically saying youre not going to marry someone or not based on their blood type)
- evolution
- changes in allele frequency over time
- heritability value
- -can never be less then 0% -can never be more then 100% importance of heredity in explaining the variation observation in some trait -used in animal breeding
- random mating: AA
- p(2)
- evolutionary force
- naturally occuring force that is capable of changing the allele frequencies within a population
- disassortative mating
- mating with someone of a different phenotype
- outbreed mating
- mating with someone who has a different genotype
- migration
- when different genotypes migrate to other locations where they previously not located (example in class with island and storm)
- sickle cell
- ss- sickle cell SS & Ss- normal
- germinal choice
- selective in eggs and sperm chosen-->IVF
- conservation genetics
- preserving various plant and animal populations
- "genetic bottleneck"
- diverse towards beginning and as time goes on becomes less diverse (shaped like a bottle turned sideways)
- captive breeding
- zoo's & botanical gardens
- gene banks
- collect seeds, stems and freeze them in a lab --> same with animals