Chapter 12.2 Unit 3 Flashcards
What does a dihybrid cross examine?
It examines 2 separate traits in a single cross
What is an example of a dihybrid cross?
RRYY x rryy
In the case of RRYY x rryy what is the 1st and 2nd parent gametes?
1= RY 2= ry
What is the rule of addition for?
The probability of an event that can occur in two or more independent ways.
What is the rule of multiplication for?
The probability that independent events will occur simultaneously.
What is testcross?
It is a cross of the individual with the unknown genotype with a homozygous recessive.
What is testcross used to determine?
The genotype of an individual with a dominant phenotype.
If the unknown is homozygous dominant all the offspring will express the what?
The dominant trait
If the unknown is heterozygous, 1/2 the offspring will express the dominant trait and 1/2 will express the what?
The recessive trait
Do most genes of Mendel’s model of inheritance meet the criteria?
No, no they do not.
What is a Pleiotropy?
It is one allele that has more than one effect on the phenotype. IE side effects
What is incomplete dominance?
It is neither dominant nor is it recessive.
What is codominance?
It is where in a heterozygous condition both alleles are expressed equally.
What can the expression of some genes be influenced by?
The environment.
What is polygenic inheritance?
It is when multiple genes control phenotype
What are continuous variation referred to as?
Quantitative traits
What is the female chromosomes?
XX
What is the male chromosomes?
XY
How many autosome pairs do humans have?
22
What is the default for humans?
Female
What does dosage compensation ensure?
It ensures an equal expression of genes from the sex chromosomes even though females have 2X chromosomes and males have only 1.
What is it called when in each female cell 1 X chromosome is inactivated and is highly condensed?
Barr body.
Describe Principal of Independent Assortment.
Genes for different traits assort independently as long as they are on different chromosomes.
