Non-medelian Genetics

Question 1

Ways traits DON’T follow the ratios predicted by Mendel’s laws

Answer 1

1. Varying degrees of dominance
2. Many traits are produced through multiple genes acting together
3. Some traits are determined by sex chromosomes
4. Some genes close to each other on the same chromosome
5. Some traits are the result of non-nuclear inheritance (chloroplast and mitochondrial DNA)

Question 2

Incomplete dominance

Answer 2

Neither allele is fully dominant
-F1 generation has a phenotype that is a mix of those of the parental generation

Question 3

Codominance

Answer 3

Two alleles for a trait are both expressed
-Ex. Human blood: AB blood, A & B both expressed

Question 4

Multiple Alleles:

Answer 4

Genes that exist in forms with more than two alleles
Ex. Human blood group, height

Question 5

Sex Chromosomes

Answer 5

Sex-linked genes: A gene located on either the X or Y chromosome
-Y and X- linked genes: Genes found on either chromosome

Question 6

Inheritance of X-linked genes

Answer 6

-Father can pass X-linked alleles to all of their daughters but none of their sons
-Mothers can pass X-linked alleles to both daughters and sons

Question 7

If an X-linked trait is due to a recessive allele:

Answer 7

-Females only express the trait if they are homozygous
-Because males only have one X chromosome, they will only express the trait if they inherit it from their mother
*hemizygous
*more likely to get x-linked disorders

Question 8

X-inactivation

Answer 8

-During development one of the X chromosomes in each cell becomes inactive
-Inactive X in each cell of a female condenses into a Barr body which helps to regulate gene dosage

Question 9

Genetic recombination

Answer 9

Production of offspring with a new combination of genes from parents

Question 10

Parental Types:

Answer 10

Offspring with the parental phenotype

Question 11

Recombinants:

Answer 11

Offspring with phenotypes that are different from the parents

Question 12

Linked genes

Answer 12

Genes located near each other on the same chromosome that tend to be inherited together

Question 13

Meiosis and random fertilization generate genetic variation in offspring due to

Answer 13

-Crossing over
-Independent assortment of chromosomes
-Any sperm can fertilize any egg

Question 14

Linked genes show parental phenotypes in offspring at higher than…

Answer 14

50%

Question 15

The further apart two genes are on the same chromosome…

Answer 15

The higher the probability that a crossing over event will occur between them and the higher the recombination frequency.

Question 16

Linkage map

Answer 16

Genetic map based on recombination frequencies

Question 17

What are map units?

Answer 17

The distance between genes

Question 18

Non-nuclear DNA

Answer 18

some traits are located in the mitochondria or chloroplasts, both are randomly assorted to gametes and daughter cells

Question 19

Chi-squared

Answer 19

Statistical analysis used to compare the actual with expected results

Question 20

Chi-square equation

Answer 20

Observed-expected 2(squared divided by) /expected results

Question 21

Critical value (chi-squared) < X2

Answer 21

reject the null hypothesis

Question 22

Critical value > X2

Answer 22

Fail to reject null hypothesis