Ch 3 Flashcards
Pure breeding verity
Homozygous for the trait desired
Monohybrid Crosses
Parents that differ in a single characteristic
Mendel’s Monohybrid crosses revealed
The principles of segregation and dominance
Principle of Segregation
Mendels first law
Each diploid organism posses two alleles (ie R and r) for any characteristic
One from mother (R) and one from father (r)
Min. 2 chromosomes
Independent Assortment (Mendells second law)
Alleles at different loci separate independently
Min. 4 chromosomes
Dominant Alleles code for
Normal, functional form of the enzyme
Backcross
A cross between the F1 and either of parental genotypes
Multiplication Rule
Probability of two separate events occurring together
AND
Obtaining a TT (a T from one parent AND a T from the other)
When rolling a die, you have a 1/6 chance of rolling a four. If you roll again, the probability of another four is 1/6.
So getting a four on the first and second role is 1/6 X 1/6 =1/36
Addition Rule
Probability of similar events occurring together
EITHER OR
Obtaining a TT, Tt, OR tt
Probability of rolling a three or a four
1/6 + 1/6 = 1/3 (2/6)
Probability of a combination of events
P= n!/s!t! p^s q^t
Event X occurring with probability p occurring s times
Event Y occurring with probability q occurring t times
!= factorial
s= number of things with one event
t= number of things with other event
n= sum of things
Wild Type
Common allele for a character
Dihybrid cross
Different in 2 Characteristics
(Shape and color)
9:3:3:1 ratios
