Transcript 2-24-10,2-25-10patternsofinheritance-Naj

Block
In
Draw a pedigree chart for your family
(grandparents, aunts, uncles, immediate
family)
Block
Through
Patterns of
inheritance A and B
OUT
C-note 492-495
Patterns of Inheritance
Open your book to page 427.
In this activity, you will begin to model
how genetic information is passed from
one generation to the next.
Process and Procedures
Part A. Inheritance of One trait
You will use 2 colors of beans to
represent the genetic information that
contributes to the trait for straight or
floppy ears in rabbits.
1. Without looking, each person selects
two beans from the cup.
2. Record the color of your beans.
Also, note whether your pair is
homozygous or heterozygous.
– Homozygous-beans are same in color
– Heterozygous-beans are different colors
3. Each person places both of their
beans in their hands and shakes them
up and selects 1 bean without looking.
– Each parent contributes only half of their
own genetic information to each offspring.
Parents do not know what half they give.
Parent 1
Parent 2
Offspring
4. Add this bean to the one your partner
selected.
5. Record the color of the 2 beans in
the new combination (offspring).
Indicate whether the new pair is
homozygous or heterozygous.
6. Use the color key provided and
answer the following questions.
Color key
Brown
Brown
Floppy ear
White
White
Straight ear
Brown
White
White
Brown
Straight ear
A. What was your 1st condition?
B. What was your partners condition?
C. What was your new (offspring)
condition?
7. As a part of a class discussion, use
the key once again and the shared
results of the class to consider the
following:
A. Did 1 bean color have a greater
influence in determining the ear trait
than the other bean color? Explain
B. Write the phenotype and genotype
for your combination of beans, your
partners, and your offspring.
– Phenotype- Straight ear
– Genotype- SS,Ss
– Phenotype - Floppy ear
– Genotype - ss
Phenotype ME
Straight
Genotype
Partner
Offspring
Straight
Floppy
ME
Partner
Offspring
Ss
Ss
ss
7c. Use genetic terminology to describe
what we did during this activity.
– List the characteristics you share with your
parents.
• For example; I have my dad’s eye shape
Part B Inheritance of Two
Traits
Today, you will work with your partner to
study the inheritance of two traits
together; ear type and sex in rabbits
1. Examine the tables in the Need to
know bow titled “Following the
Inheritance of Two Traits”.
– Floppy ears or straight ears
– Male rabbits or female rabbits
2. Based on the results, what
conclusions can you draw about these
two traits?
3. Male rabbits that had straight ears
were mated with female rabbits with
floppy ears. Calculate the data for
sex and ear type as percentages.
Percntage with trait=[(#with trait)÷(total #offspring)] X 100
Male %
Female %
Floppy %
Straight %
4. Discuss the following with your table and
record answers.
A. What overall conclusions can you draw
about the inheritance of straight ears versus
floppy ears?
B. Do you think the type of ear a rabbit is
born with is affected by whether a rabbit is
female or male? Explain
Analysis questions
2. Restate the following accurately,
One out of every two offspring that
result from a cross between parents
with the genotypes Hh and hh definitely
will have Huntington’s disease.
3. Two healthy individuals marry and
produce three children. The first two
are healthy. But the third is born with
cystic fibrosis alleles. What can you
conclude about the genotypes of the
other people in the family?
5. In cocker spaniels, black B is dominant over
red b. Solid color S is dominant over white
spotting s. A red male was mated to a black-andwhite female. They had five puppies, as follows:
one black, one red, one black and white, and two
red-and-white.
A. What genetic principle explains the
phenotypes of these offspring?
B. Write a one or two paragraphs to describe
how that principle worked in this cocker
spaniel family. Include the following terms;
gene, phenotype, dominant trait, recessive
trait, chromosome, allele, genotype