Download Genetics Review Lectures 1-4

Genetics Review
Lectures 1-4
BIO250 Genetics
Dr. Ramos
Offspring
look like
their
parents.
WHY?
Class divided in 3 parts:
• Mendelian Genetics
– Ratios, monohybrid, dihybrid crossed
• Molecular Genetics
– DNA replication, translation, linkage
• Current topics
– Bioethics, reading scientific literature
Genetics in every day life
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•
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Agriculture
Forensics
Medicine
Conservation
Biotechnology
In November we will
discuss some of the
bioethical implications of
the use of genetics in
different fields. Every
student will do a small
presentation on a topic.
Mendelian Genetics
• Model organisms
– Short life cycle
– Large number of offspring
– Easy to grow
– Occupy small space
– Easy to provide nutrients for
– Well understood growth and development
Seven traits analyzed by Mendel
Phenotype: physical appearance of a trait
Gene: unit of inheritance
Allele: alternative forms of a single gene. Determines phenotype.
Genotype: genetic makeup of an individual.
Homozygous: both alleles are the same
Heterozygous: both alleles are different.
Mendel figured out the rules of genetics by
working with pea plants. Why were these plants
a good tool for Mendel to use to answer his
questions about inheritance?
1. Individual plants could be self-fertilized or crossfertilized with other individuals.
2. They grew quickly (short generation time).
3. Clearly defined traits (yellow vs. green) were
observed.
4. All of the above.
Mendel’s Postulates
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Unit factors exist in pairs.
There are dominant and recessive factors.
Paired unit factors segregate randomly.
Independent assortment
Monohybrid, Dihybrid and Trihybrid crosses
A dominant trait
masks the effect of a
recessive trait.
Which example is the genotype of a
true-breeding plant?
1. Two copies of the purple allele
2. Two copies of the white allele
3. One copy of the purple and one copy of
the white allele.
4. 1 and 2
5. All of the above
Which answer below is an example
of a heterozygous plant?
1. Two copies of the purple allele
2. Two copies of the white allele
3. One copy of the purple allele and one copy
of the white allele
4. 1 and 2
5. All of the above
A flower that is heterozygous for the purple gene
(Purple “P” is dominant over white “p”) has what
phenotype and genotype, respectively?
1.
2.
3.
4.
5.
Purple; PP
Purple; pp
White; Pp
White; pp
Purple; Pp
Glossary sheet