mendelian genetics extended Flashcards
what is the first law of segregation (Mendel’s law)
Genes segregate at meiosis so that
each gamete contains only one of the
two possessed by the parent
dihybrid cross
9:3:3:1
what is the product rule?
independent events (whats happening at one doesn’t influence others)
what is the second law of segregation (Mendel’s law)
Alleles of different genes assort
independently during gamete formation
what is polymorphic?
a lot of different alleles for one gene (each individual can only have 2 alleles, one on each
homologous chromosome)
what is co-dominance?
Where both phenotypes exist side by side within the organism
what are polygenic traits?
Phenotype controlled by many genes that have
an additive effect
what is the additive effect?
all the genes of the polygenic trait contributing to some way ( eg skin,height,IQ )
what is the product rule?
independent events (what’s happening at one doesn’t influence others)
what is the polygenic traits?
Phenotype controlled by many genes that have
an additive effect
what is the additive effect?
Multiple genes are contributing one way or another – but their effects are added together to create a phenotype
what plays a huge part in phenotypes?
environment plays a huge part in the phenotypes and genetic makeup
what is the monohybrid ratio?
3:1
how to find out the probability of getting a ssyy offspring from a SsYy x SsYy cross easier way?
break it down gene by gene
what is the genotype?
combination of alleles
why must we multiply each parent’s probability when finding out the total probability of that genome?
we must multiply the probability because the events are independent of each other since whatever happened in parent 1’s sperm had no influence in parent 2’s eggs
what is the product rule?
when two events are independent we multiply them together
what would happen if both parents could give out each of the resultant gene?
- find the probability of each possibility
- plus both of the outcomes
- final probability of getting that gene
what is the sum rule?
mutually exclusive events are (a or b) and you add them together
what’s the probability of BB?
1 because both ways you get one B
how do new alleles arise?
through mutation
what is phenotype?
its what you can see
what is typical of polygenic trait?
- normal distribution is typical of polygenic trait in a population
- most people in the middle of the bell curve
- less likely to be at the extreme points
how to get a higher number of phenotypic classes?
get more genes involved
