lec1 - mendelian laws Flashcards
difference btwn vertical and horizontal pattern of inheritance?
horizontal - pedigree chart looks like a sandwich, skipping generations
vertical - pedigree chart looks like a vertical sandwich
common results of recessive mutations vs dominant?
(e.g. recessive results in ___ of function)
recessive - loss
dominant - gain
examples of single-gene recessive traits?
thalassemia, sickle-cell anemia, cystic fibrosis, PKU, red-green colour blindness, PKU, tay-sachs disease
(not sure if need to know tho)
examples of single-gene dominant traits?
huntington disease, hypercholesterolemia
define monohybrids
individuals with two different alleles for a single trait
what is mendel’s law of segregation?
a diploid individual possesses a pair of alleles for any particular trait and each parent passes one of these randomly to its offspring.
- Each plant possesses two alleles for each trait.
- Two alleles for each trait separate during gamete formation.
- Gametes contain one allele for each trait.
- Two gametes, one from each parent, unite at random at fertilisation.
- Combinations of two alleles in one individual is either in a homozygous or heterozygous state.
what is mendel’s law of independent assortment?
states that the alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.
what are two methods to study inheritance?
punnett square and pedigree charts
[punnett square] - MATH TEST!
what is the product rule? (i.e. P(1 and 2) = ?)
what is the sum rule? (i.e. P(1 or 2) = ?)
product rule:
P(1 and 2) = P(1) x P(2)
sum rule:
P(1 or 2) = P(1) + P(2)
for a dominant WT and recessive mutant,
how to test if an individual with WT phenotype is heterozygous or homozygous?
test cross with homozygous recessive.
in mendel’s pea example, where YY/Yy = yellow peas and yy = green peas,
If individual is YY, progeny (YY x yy) produces only Yy (yellow peas).
If individual is Yy, progeny (Yy x yy) produces 1:1 Yy (yellow) : yy (green).
what does double line between male and female on a pedigree chart mean? (macam double bond)
consanguineous mating (aka incestuous sex)
how to denote normal, trait expression and carrier on a pedigree chart?
male - square, female - circle.
normal - unshaded shape
affected - shaded shape
carrier - half shaded, half unshaded (vertical separation)
what constitutes an autosomal recessive trait?
(hint: gender; generational differences; what genotype would the parents of an affected individual have?)
- males and females can be affected
- affected males and females can both transmit the gene (unless death before reproduction)
- trait can skip generations
- parents of affected individual are heterozygous or affected.
what would a pedigree chart with auto. recessv trait look like?
- horizontal mode of inheritance (skipping gens)
- all children of two affected parents are all affected
what mode of inheritance could an auto recessv trait show if it is extremely common in the population?
vertical
what mode of inheritance could an auto recessv trait show if it is rare in the population?
horizontal
