Bio J Genetics Study Guide 10-11
TO BE COMPLETED ON A SEPARATE PIECE OF PAPER
I.
Mendel and a little History:
Describe Mendel’s experiments. Include the two generations and their offspring, his expectations and any
surprises he encountered.
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What term did he use to describe his parent generation and what does this mean?
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Now that we know about alleles and genotypes, what other word could be used to describe these parents?
Describe the law of segregation: what is it? What happens during meiosis to allow it to occur? What
significance does it have in the offspring?
Describe the law of independent assortment: What is it? What happens during meiosis to allow it to occur?
What significance does it have in the offspring? What sorts of genes might not independently assort and
why is it still possible even for these genes?
II.
Genes vs. alleles
Describe the relationship between genes and alleles and provide examples of each.
How many alleles for each gene are found in a gamete? How many alleles for each gene are found in a
zygote?
If a gene is said to contain “multiple alleles” what do we mean? How many alleles do we inherit for such a
gene? Provide an example of such a trait in humans.
How does a polygenic trait differ from a trait that has multiple alleles?
III.
Inheritance patterns and Punnett Squares
What do the different squares of the punnett square symbolize?
Why do we say that punnett squares have to do with probability and not absolute outcome? What does
“sample size” or “sampling error” have to do with this?
You will need to be able to solve monohybrid or dihybrid crosses with any of the following inheritance
patterns:
1. complete dominance
2. incomplete dominance
3. co-dominance
4. X-linked
- Use your problem packet, your book or the unit resource page of our website to practice these problems.
You will NOT see any of these exact problems on the test, so it is important that you study how to solve
the problem not the exact problem itself.
On your study guide, compare the four different types of inheritance problems in terms of the following
a. How do the alleles behave when together?
b. What clues might be in the problem to help you identify the type of inheritance?
IV.
Test Crosses:
What is the purpose of a test cross? Where would this have any practical application?
How is a test cross done? What information can we learn from a test cross and how? Why it is only
necessary for traits that display complete dominance?
V.
Pedigrees:
What are the symbols used in a pedigree and what do they stand for?
Be able to draw a pedigree given a verbal description of a family using genetic terms.
Be able to choose the most likely inheritance pattern that fits a particular pedigree
List “clues” to look for that might suggest a pedigree shows a trait that is:
a. Autosomal dominant
b. Autosomal recessive
c. X-linked recessive
VI.
Specific Genes: most examples of genes will be described in a way that you’ll be able to figure out
the inheritance pattern. The following are examples of genes that you are EXPECTED TO KNOW
how they are inherited.
a. Human blood type: what are the alleles? What inheritance pattern(s) are demonstrated?
b. Color blindness: Is this autosomal or X-linked? Dominant or recessive?
Vocabulary: In addition to any terms above, you are expected to know the meaning AND USE the following
words if necessary in your explanations
Dominant
Progeny
P, F1, F2
Recessive
Genotype
Autosome
Locus
Phenotype
Linkage
Haploid
Homozygous/pure
Diploid
Heterozygous/hybrid