1. Mendelian Genetics and Complex Inheritance
Trashketball review

2. What does Mendel’s Law of Segregation state?
two alleles for each trait separate during meiosis.

3. In some breeds of chickens, white feather and black feather can appear together producing a heterozygous color pattern that is known as erminette. If two erminette chickens were crossed what is the probability …
A) they would have white chickens –
B) they would have black chickens-
A) 25%
B) 25%

4. IAIB x IA Ii IAIB x IAIA A 50% A 50% B 25% B 0% AB 25% AB 50% 0% O 0%
An individual with blood type AB marries some one with blood type A. What is the probability they will have children with type A blood, type B blood, type AB, or type O? Include all possibilities.
IAIB x IA Ii IAIB x IAIA
A 50% A 50%
B 25% B 0%
AB 25% AB 50%
0% O 0%

5. A woman who is albino marries a man who is not albino
A woman who is albino marries a man who is not albino. They have a child that is albino. What is the genotype of the man? Heterozygous Aa for albinism.

6. Why is Gregor Mendel considered the “Father of Genetics”?
His work allowed us to understand heredity and make predictions about the probability of traits being passed from parent to offspring.

7. For sex- linked traits, why can males never be carriers?
They only have one copy of the X chromosome. What they inherit on that chromosome will be expressed.

8. In snapdragons red flowers and white flowers are incompletely dominant
In snapdragons red flowers and white flowers are incompletely dominant. A pink flower plant is crossed with a red flower plant what is the probability they will produce . . .
A) white flowered plants?
B) Pink flowered plants?
A) 0%
B) 50%

9. How many chromosomes does a human being have?
How many autosomes does a human being have?
46 chromosomes/ 44 autosomes

10. What does Mendel’s Law of Independent Assortment state?
Random distribution of alleles occurs during gamete formation

11. Two parents are heterozygous for sickle cell disease
Two parents are heterozygous for sickle cell disease. What is the probability of them having a child that is homozygous for the disease?
25% probability

12. Two parents think their baby was switched at the hospital
Two parents think their baby was switched at the hospital. The mother has type O blood and the father has type AB. The baby has type B blood. Was the baby switched? (include a Punnett square for your answer.)
The blood type is possible if the child in heterozygous (IBIi) for blood type. IA IB
I i
IAI i
IBIi Ii
IAIi

13. What is the difference between genotype and phenotype?
Genotype: The genetic makeup of an individual
Phenotype: The physical appearance of an organism. How the genes are expressed. Genotype controls phenotype.

14. Brown eyes are dominant to blue eyes
Brown eyes are dominant to blue eyes. An individual with blue eyes marries someone with brown eyes. They have a daughter who has brown eyes. The daughter marries and has a son who has blue eyes. What is the genotype of the daughter?
Daughter= Bb

15. In fruit flies red eye color (R) is dominant to white eye color (r)
In fruit flies red eye color (R) is dominant to white eye color (r). In a cross between two fruit flies 50% of the males and 50% of the females had red eyes. The other half of the males and females had white eyes. What are the genotype and phenotypes of the parent flies?
XrY x XRXr
Male with white eyes and female with red eyes.

16. What are two sex- chromosomal disorders we discussed and what are symptoms of each?
Turner’s Syndrome- Only viable monosomy
Klinefelter’s syndrome- Male sex organs and female body characteristics. Normal Intelligence.
XYY- tall male with heavy acne
XXX- fertile female with normal intelligence

17. Why are recessive sex-linked traits also referred to as X- linked traits?
Sex- linked traits occur on the X sex- chromosome.

18. What is dosage compensation and what does it ensure?
Dosage compensation happens when one X chromosome is inactivated. This allows for equal level of expression from sex chromosomes.

19. A wealthy elderly couple die together in an accident
A wealthy elderly couple die together in an accident. Soon a man shows up to claim their fortune, saying that he is their only son who ran away from home as a boy. Other relatives dispute his claim. Hospital records show that the deceased couple were type AB and O respectively. The claimant to the fortune was type O. Could he be their son? NO

20. In a marriage of two non- hemophiliac parents they have a son who is hemophilic. What is the probability of the couple giving birth to sons who are hemophiliac and to daughters being hemophiliac?
XHXh x XHY
50% chance for hemophiliac son and 0% chance for hemophiliac daughter.

21. In pea plants tallness (T) is dominant to shortness (t) and axillary flowers (A) are dominant to terminal flowers (a). Two plants who are heterozygous for both traits are crossed. What are the expected phenotypes and their ratios of the offspring?
Tall axillary 9
Tall terminal 3
Short axillary 3
Short terminal 1

22. For sex-linked traits, why do sons always inherit the trait from their mother? Because the mother donates the X chromosome to her son. What ever trait is on the X chromosome is the one that will be expressed.