Genetics Review
Define the following Genetic Terms (create flash cards):
-Allele
-Genotype
-Phenotype
-Dominant
-Recessive
-Homozygous
-Heterozygous
-Complete Dominance
-Incomplete Dominance
-Codominance
-Nondisjunction
-Monosomy
-Trisomy
Punnett Squares
-Know how to set up a punnett square
-Know how to determine the genotypic and phenotypic ratio of a punnett square
- Example = 3: 1 1:2 :1
Brown : BlueBB : Bb: bb
-Know how to determine the probability (percentage)
- Example = 25% Blue Eyes
EXAMPLE: Red flowers are dominant to white flowers. Show the heterozygous red flower crossed with a white
flower.
Key:
Parent genoypes:
Offspring Genotypes AND Phenotypes:
What is the genotypic ratio?
What is the probability of having an offspring with white flowers?
Polygenic Traits =
-Ex: Hair, Skin, Blood
-Know how to determine Blood types
- Type A = and
- Type B = and
- Type AB =
- Type O =
EXAMPLE: Two other parents think their baby was switched at the hospital. The mother has blood type “AB,” the
father has blood type “O” and the baby has blood type “B”
a. Mother’s genotype: ______
- Father’s genotype: ______
- Baby’s genotype: ______or ______
- Using evidence from a punnett square, EXPLAIN if it is possible
for the baby to belong to these parents
Sex Chromosomes
-Female = XX
-Male = XY
-Sex Linked Traits
- Color Blindness
-Pedigree
- Which shapes represent female
- Which shapes represent males
- What represents a normal male
- What represents a normal female
- What represents a carrier
- What represents an affected person
- What represents a dead person
- What is the symbol for siblings
- What is the symbol for a married couple
EXAMPLE: In humans, hemophilia is a sex-linked recessive trait. If a female who is a carrier for
hemophilia marries a male with normal blood clotting, answer the following questions.
Parent Genotypes: ______x ______
- What is the probability the female children will have hemophilia?
- What is the probability the female children will be carriers?
- What is the probability the male children will have normal blood clotting (be healthy)?
- What is the probability the male children will be carriers?
- What is the probability the children will have hemophilia?
Mutations
-Know how to read Karyotypes to identify sex and mutations
-Monosomy example = Turner Syndrome (XO)
-Trisomy examples =
- Klinefelter Syndrome (XXY)
- Down Syndrome (extra chromosome on 21)
Explain the karyotype below
Is this a male or female?
Does this karyotype have any abnormalities?
What disorder is shown in this karyotype?
Is there a trisomy or monosomy disorder? Explain your answer with evidence.
Pedigree:
Know the symbols for:
Female =
Male =
Dead =
Married =
Siblings =
Infected (Disorder) =
Carrier =
Example: On next page
Trait: Falconi anemia
Forms of the trait:
The dominant form isnormal bone marrow function - in other words, no anemia.
The recessive form is Falconi anemia. Individuals affected show slow growth, heart defects,
possible bone marrow failure and a high rate of leukemia.
A typical pedigree for a family that carries Falconi anemia. Note that carriers are not indicated with half-colored shapes in this chart.
Analysis Questions.
To answer questions #1-5, use the letter "f" to indicate the recessive Falconi anemia allele, and the letter "F" for the normal allele.
1. What is Arlene's genotype?
2. What is George's genotype?
3. What are Ann & Michael's genotypes?
4. Most likely, Sandra's genotype is .
5. List three people from the chart (other than George) who are most likely carriers of Falconi anemia.