Chapter 14: Mendel and the Gene Idea Flashcards
What is true-breeding?
Completely homozygous parents passing on
What is hybridization?
Cross between two true-breeding varieties
Versions of genes are called _______.
Alleles
What is a locus?
Area of chromosome that holds the gene
What is the genotype?
The actual genetic ratio
What is the phenotype?
The visual ratio
What is the Law of Segregation?
When heritable traits are hidden and then reappear
When a heterozygous crosses with another heterozygous
(When two alleles in a pair segregated into different gametes during gamete formation)
What is the law of independent assortment?
Hereditary alleles assort randomly during gamete production
Alleles assort independently of each other, such as round/wrinkled vs yellow/green
What is testcrossing?
Do either:
PP x pp
Pp x pp
This is to figure out if the dominant gene is homozygous or heterozygous
To determine the genotype of a round pea plant it should be crossed with ____________________.
Homozygous recessive plant
What is a dihybrid cross?
Looking at two traits simultaneously
Eg, peas
What is incomplete dominance?
Neither gene is dominant, but there is a blend.
Pink is considered the “intermediate phenotype”
Red + white = pink
What is codominance?
Neither gene is dominant, but there is a mixture of the two.
Black + white = black and white spots
For incomplete dominance and codominance, how do you write the punnet squares?
Red: C^r
White: C^w
Pink: C^r C^w
Which of the following represents a gamete that the dihybrid plant (YyRr) could form?
A. Yy
B. Rr
C. YR
D. YyRr
C. YR
Because YyRr would give one trait from the mother and one trait from the father, which would be:
YR
Yr
yR
yr
What are multiple alleles and what’s an example of them?
3 or more alleles for a specific gene
Eg, blood groups
What are the genotypes for blood group A, B, AB, and O?
A - IA IA or IA i
B - IB IB or IB i
AB - IA IB
O - ii
True or false:
The blood type of a child who’s parents blood types are A and B could be A, B, AB, or O.
True
Do a punnet square
What is epistasis?
When one gene affects the expression of another gene
Gene 1: lab fur colour
Gene 2: permission of pigment
What does this mean:
The gene for pigment deposition is epistatic to the gene for lab colour.
The gene for pigment disposition is more important (dominant) than the gene for fur colour
What is pedigree analysis?
Chart of traits in humans
What is significant about having a recessive disorder?
If you’re heterozygous for a recessive disorder, you will not have that disorder. If you are heterozygous you only “carry” it.
DD = you do not have the disorder Dd = you carry the disorder dd = you have the disorder
What is significant about having a dominant disorder?
If you are heterozygous for a dominant disorder, you will have that disorder.
DD = you have the disorder Dd = you have the disorder dd = you do not have the disorder
