DNA
MUTATIONS &
GENETICS
LEWIS BIOLOGY 2013
CONCEPTS COVERED THIS UNIT
Mutations (Point and Frame-shift)
Diseases caused by Mutations
Sickle Cell Anemia and Point Mutations
Genetics and Heredity
Gregor Mendel and the Pea Plants
Monohybrid Crossing
Alleles
Mendelian Genetics
Non-Mendelian Genetics
Dominance vs. Recessive
Co-Dominance
Incomplete Dominance
Multiple Alleles & Blood Typing
Sex-Linked Traits
Pedigree Analysis
Chapters 10 & 12-13
are a good resource to
use for this unit!
Please read ahead
TERMS YOU WILL ENCOUNTER THIS
UNIT
(AT SOME POINT YOU WILL NEED THIS VOCABULARY IN YOUR
NOTES)
Heredity
Trait
Genetics
Gamete
Fertilization
Zygote
Pollination
Hybrid
Allele
Dominant
Recessive
Phenotype
Genotype
Homozygous
Heterozygous
Crossing over
Diploid
Haploid
Egg
Homologous chromosomes
Meiosis
Nondisjunction
Sperm
Sexual reproduction
Carrier
Fetus
pedigree
Co-dominance
Incomplete dominance
Multiple allele
Polygenic inheritance
Sex chromosome
Sex linked trait
Karyotype
DISEASES COVERED
THIS UNIT
Please research and read ahead about the following genetic disorders:
Kleinfelter’s Disease
Turner’s Syndrome
Cystic Fibrosis
Sickle Cell Anemia
Trisomy 21 (Down Syndrome)
THE EXAM FOR THIS
UNIT
The exam for this unit will be held between October 30-31st.
This will be considered your Midterm Examination.
Most of the material will cover: DNA, RNA, Protein Synthesis
and Genetics—although older material will be on the exam.
The midterm will be weighed twice (as two test grades)
Please study ahead of time as it is comprehensive and
cumulative.
As a resource, utilize Chapters 10 & 12 in the Blue Glencoe
Textbook
DNA MUTATIONS
There are two general types of mutations
Point and Frame-Shift
Mutagen: something that causes a mutation
Point Mutations: a genetic mutation in which only one of the nitrogenous
bases is substituted (changed) to another). Only one amino acid is
changed
Frame-shift Mutations: a genetic mutation in which one of the bases is
added or deleted. This causes the rest of the DNA sequence to shift,
changing the ENTIRE DNA/AMINO ACID SEQUENCE. THIS IS THE MOST
DANGEROUS MUTATION
EXAMPLES OF POINT
MUTATION
Sickle cell anemia is caused by a point mutation.
A single base is changed, causing the disease to occur
(FYI, those who have sickle cell are resistant to Malaria)
Normal Hemoglobin (blood)
GGG-CTT-CTT-TTT
Sickled Hemoglobin (blood)
GGG-CAT-CTT-TTT
Only one(1) of the amino
acids will change
EXAMPLES OF FRAME-SHIFT
MUTATIONS
One of the bases in a DNA sequence is either inserted or deleted,
therefore causing the entire sequence to shift.
This will change the entire DNA sequence, thusly changing the entire
AMINO ACID SEQUENCE.
THIS CAN BE LETHAL
NORMAL SEQUENCE:
ATC – GAT – TTA – AAG
THE A WILL BE DELETED, AND THE REST OF THE BASES WILL SHIFT
TO FILL ITS PLACE
MUTATED SEQUENCE: ATC
– GTT – TAA –AG…..
ASSIGNMENT #1:
MUTATIONS WORKSHEET
Complete the mutations worksheet on my
website. This is to be completed on your
own paper.
The answers will be discussed on today’s
meet www.todaysmeet.com (please remember
guidelines for appropriate commentary) Lets not allow for immaturity
to ruin the privileges of those who follow rules.
Be sure to read the section on your
worksheet about Sickle Cell Anemia.
GENETICS
&
HEREDITY
CHAPTERS 10 &12
FATHER OF GENETICS
Gregor Mendel is the father of genetics (hence the term
Mendelian Genetics).
• Mendel was an Austrian monk studied heredity (how traits
are passed from parent to offspring)
• He was the first to be able to predict the outcome of one’s
traits.
• This led to the field of genetics (branch of biology that
studies heredity)
• He studied heredity using garden pea plants using the sex
organs (yes, plants reproduce sexually..)
THE BIRDS & THE
BEES…WELL JUST THE
PLANTS
IN PLANT FERTILIZATION, THE MALE GAMETE UNITES
WITH THE FEMALE GAMETE. THIS RESULTS IN A ZYGOTE
ZYGOTE
TERMS &
ABBREVIATIONS
• Monohybrid cross: aka the ‘Punnett Square’, used to predict the traits
of offspring
• P1: Parent generation (mom & dad)
• F1, F2, ..: Filial generations (the offspring, grandchildren etc.)
• Homozygous Dominant: AA
• Homozygous recessive: aa (this is the ONLY time recessive traits are
shown)
• Heterozygous: Aa (the dominant trait is still expressed)
• Dominant: trait that is shown or expressed
• Recessive: trait that is hidden or disappears in the mating
• Alleles: forms of a gene
…MORE TERMS
Joke: You’ve
got some good
jeans! Haha…
Get it??
Phenotype= the Physical appearance (color, size,
shape, etc.)
Genotype = the gene or allele (Aa, AA, aa)
Example:
75% of the Offspring were Heterozygous Aa (genotype),
meaning, they have Yellow eyes (phenotype)
25% of the offspring were Homozygous recessive aa
(genotype), meaning they have white eyes (phenotype)
BASICS OF THE PUNNETT
SQUARE: TRY THIS EXAMPLE
Alleles: Brown eyes: BB, Bb
Blue Eyes: bb
A
a
a
a
Problem:
Mom has blue eyes, and Dad is
Heterozygous for Brown eyes.
Complete the Punnett Square and
give the phenotype and genotype of
the offspring
BASICS OF THE PUNNETT
SQUARE: ANSWER
Problem:
Mom has blue eyes, and Dad is
Heterozygous for Brown eyes.
Alleles: Brown eyes: BB, Bb
Blue Eyes: bb
A
a
a
a
Aa
aa
Aa
aa
Complete the Punnett Square and
give the phenotype and genotype of
the offspring
Answer:
Phenotype:
50% will have brown eyes
50% will have blue eyes
Genotype:
50% Aa (heterozygous)
50% (homozygous recessive)
ASSIGNMENT #2
Complete the Monohybrid Cross worksheet on my website.
The worksheet has been upload, you may write your answers
on your own paper OR print it at home!
Do not forget the rules of Mendelian Genetics!!!
If there is a capital letter (A, B, C…), this means the gene is
dominant, and will mask (cover) the recessive gene (a, b, c)
MEIOSIS
…NOT SEXUAL REPRODUCTION
REMEMBER…
We covered Meiosis when we talked about Mitosis.
Meiosis is a cell division of gametes…
In other words---it’s
how guys make sperm, and
ladies make eggs (ladies, you’re born with
the eggs you have ) Guys continue
Meiosis until they’re old…yuck
Meiosis is NOT SEXUAL REPRODUCTION
MEIOSIS
In Meiosis, it’s a way of taking a person’s 46
chromosomes, and dividing them in half—so that
parents only pass 23 chromosomes onto their
offspring.
You’re the perfect blending of both of your parents.
46 chromosomes in dad’s sperm / 2 (meiosis) = 23
chromosomes
46 chromosomes in mom’s eggs / 2 (meiosis) = 23
chromosomes
23 chromosomes + 23 chromosomes = YOU 
REVIEW: MITOSIS VS. MEIOSIS
Mitosis
Meiosis
Number of Divisions
1
2 (Meiosis I & Meiosis II)
Number of daughter cells
2
4
Purpose
Making new body cells
(liver, hair, skin, etc.)
“somatic cells”
Making new sex cells
“gametes” (sperm &
eggs)
Chromosome #
Diploid (2n)
Haploid (n) -half
MEIOSIS VS MITOSIS
Organism
Somatic cell (Mitosis)
Diploid (2n)
Gamete (meiosis)
Haploid (n)
Fruit fly
8
4
Garden pea
14
7
Corn
20
10
Tomato
24
12
Leopard frog
26
13
Apple
34
17
Human
46
23
Chimpanzee
48
24
Dog
78
39
Adder’s tongue fern
1260
630
EVENTS IN MEIOSIS
Crossing Over: Occurs in Prophase I, where the chromosomes
break, and exchange genetic material
Nondisjunction: where the chromosomes fail to separate during
Meiosis, this causes Trisomy 21 (Down Syndrome)
Crossing over
TO BE
CONTINUED
…NON-MENDELIAN GENETICS