Biology: October 2014

Karyotypes:

Punnet Square:

(Video reviews vocabulary)

Punnet Square Practice: http://www.zerobio.com/drag_gr11/mono.htm
Practice Questions: http://www.quia.com/quiz/220564.html

Pedigree:

Pedigree Practice: http://biologycorner.com/worksheets/Pedigrees%20Practice.pdf

Practice for all:

Name: ____________________

Punnett Square, Pedigree and Karyotype Practice

Vocabulary. Define the following words.

Pedigree

Karyotype

Sex-linked Inheritance

Autosome

Sex Chromosome

1. In seals, the gene for the length of the whiskers has two alleles. Long whiskers are

dominant, short whiskers are recessive. We use the letter “w” to describe whisker length.

a. Write the homozygous dominant genotype. __________

b. What is the phenotype for the genotype above (#a)? ___________

c. Write the heterozygous genotype. ______

d. What is the phenotype for the genotype above (#c)?________________

e. Write the homozygous recessive genotype.________

f. What is the phenotype for the genotype above (#e)?________________

g. In a cross between a homozygous dominant papa seal with a homozygous recessive mama seal, what

percentage of the offspring would be expected to have long whiskers?

Punnett Square: % with long whiskers?

h. In a cross of two heterozygous parent seals, what percentage of the offspring would be expected to have short whiskers?

Punnet Square: % with short whiskers?

2. In purple people eaters, one-horn is dominant and no horns are recessive. A homozygous dominant purple people eater mates with a no-horned purple people eater.Use H and h for alleles.

a. What are the genotype probabilities of the offspring? ________________

b. What are the phenotype probabilities of the offspring? _______________

3. In Gateway gators, blue is the dominant skin color (B), red is recessive (b). But a cross between a blue gator & a red gator produces a purple gator (Bb).

a. What pattern of inheritance does this illustrate? ____________________

b. If a purple gator is crossed with a blue gator, what is the chance the baby will be red? ___________

Blood Type Problems

1. List all the possible genotypes for each of the 4 blood types (Use I^A, I^B, and i):

Type O ____________ Type B______________

Type A ____________ Type AB_____________

SHOW WORK FOR PROBLEMS BELOW!

2. A man with AB blood is married to a woman with AB blood. What blood types will their children be and in what proportion?

3. A man who has type B blood (genotype: BB) is married to a woman with type O blood. What blood type will their children have?

4. A woman with type A blood (genotype: AO) is married to a type B person (genotype: BO). What blood types will their children have?

5. A woman with type A blood is claiming that a man with type AB blood is the father of her child, who is also type AB. Could this man be the father? Show the possible crosses; remember the woman can have AO or AA genotypes.

6. A man with type AB blood is married to a woman with type O blood. They have two natural children, and one adopted child. The children's blood types are: A, B, and O. Which child was adopted?

7. A person with type O blood is married to a person with type A blood (unknown genotype). They have 6 children, 3 of them have type A blood, three of them have type O blood. What is the genotype of the two parents?

Pedigree Problems

1. Huntington’s disease is a dominant disease. Individuals who are homozygous dominant and heterozygous get the disease, but individuals who are homozygous recessive do not get the disease.

a. What are the genotypes of people who get Huntington’s disease? _________________________

b. Both parents are heterozygous for the Huntington’s allele. What is the chance that their child will not have Huntington’s disease? _______________________________

2. Which people are affected?

What shape represents a male?

What shape represents a female?

How do you know if people are married?

How do you know if people are siblings?

3. Is the allele for widow’s peal dominant or recessive?

Make a punnett square for the 4^th generation (hint: if the 3^rd generation has a baby)

4. What is the genotype of the affected people?

Why is there a “?” for some of the people?

Which generation has 2 affected siblings?

Is there any explanation for the higher frequency of affected people in this generation (from above)?

Karyotype Problems

A chart of chromosome pairs is called a karyotype. This is collected from a sample of cells from an individual or fetus. Metaphase chromosomes are photographed, and the chromosome pictures are enlarged, cut apart and arranged in pairs on a chart according to length and location of the centromere.

How many pairs of chromosomes do humans have?
Is this person male or female? How can you tell?
The sex of an individual is determined by what? The number of X chromosomes or Y chromosomes?
Examine the pedigree, what is wrong with karyotype? What location is the disorder?
This is called Trisomy 21 or Down Syndrome. What is this disorder?