Review for Mendelian Genetics
1. What is shown in a pedigree?
2. How do you find the genotype of individuals on a pedigree?
a. Autosomal Dominant:
b. Autosomal Recessive
c. Sex-Linked Recessive
3. How are the following represented in a pedigree:
a. a normal male/a male that shows the trait
b. a normal female/ a female that shows the trait
c. a child
d. a marriage
e. generations of the family
BACKGROUND INFORMATION
Excessive toe jam (ETJ) is recessive to normal amounts of toe jam. Look at the information
below about the Scholl’s family. Design a pedigree showing how ETJ has been passed in this
family. Under people on the pedigree, put their genotype. Use T for dominant and t for
recessive.
Use the following information to label a pedigree for the Scholl family.
1. Henrietta has never heard of ETJ in her family.
2. Grandpa has normal toe jam.
3. Sue has normal toe jam.
4. Barney has ETJ.
5. Lynn has ETJ.
6. Doris’s mom has ETJ.
7. Sue marries Joe who has ETJ.
8. Bob has ETJ.
9. Grandma has ETJ.
10. Sue and Joe have four daughters with normal toe jam.
11. Jack has ETJ.
4. What is an autosome?
5. How many sex chromosomes are found in a normal karyotype?
6. How can you tell if someone is male or female by the karyotype?
7. What happens during nondisjunction? What are the 2 terms used for the result?
8. What determines the sex of the offspring? (What chromosomes are present in a
male, what chromosomes are present in a female?)
9. What is the sex of the person in the karyotype below?
10. Is the karyotype below normal or abnormal?
If abnormal, put a circle around the abnormality and name the disorder.
.
11. What does genetics study? (one word)
12. What is an allele?
13. If you flip a coin, what is the probability it will land heads up? Explain why.
14. What is the difference between dominant and recessive alleles?
15. Compare and contrast genotype and phenotype?
16. How are heterozygous and homozygous alleles expressed?
17. What is incomplete dominance? Ex?
18. What is codominance? Ex?
19. What is codominance with multiple alleles? Ex?
20. How many chromosomes are in a normal human cell?
21. Do the following Monohybrid cross. (R-red, r-white)
Cross a homozygous white flower with a heterozygous red flower.
P1: __________________ x _________________
List the genotypes and phenotypes and their ratios
Genotypes:
Phenotypes:
22. Complete the following Dihybrid cross. (W-black hair, w-white hair, B-black eyes,
b-brown eyes)
Cross two heterozygous black hair, black-eyed mice
P1: ________________ x _________________
Again list the genotypes and phenotypes and their ratios
Genotypes:
Ratio:
Phenotypes:
Ratio: