PMHS
AP PSYCH
Name________________________________________
AIM: To understand the influence of epigenetics on gene expression
Chromosomes
DNA
Genes
Mnemonic
Phenotype
Genotype
Heterozygous: different homozygous: same
alleles: forms of a gene found on the same place on a chromosome
Perform a punnett square of offspring of two heterozygous brown CATS.
% brown phenotype:
genotypes for brown cats:
% grey phenotype:
genotypes for grey:
Punnett Square between heterozygous hitchhiker parents
Hitchhiker thumb* this may not be
best example of basic genetics – could be polygenetic, many pairs of alleles
Thanks to Utah Genetics for basics and U Del professor for “myths”
***THE EXAMPLE ABOVE IS NOT a two-trait allele!!!
What can be more surprising, is that identical twins could have the same genotype,
but a different phenotype!!!! Explain using the phrase EPIGENETICS and agouti
mice study from NOVA/Duke
_____________________________Environmental factors can alter the way our
genes are expressed, making even identical twins different.
What can be learned about epigenetics when it comes to a mother rat licking her
pups?
What are the differences between epigenome, genome, chromosomes, DNA, genes
MUTATIONS
PRACTICE
1. Genes are
A.found in the cytoplasm of a cell
B.found on chromosomes
C.found in the cell wall
2. A CHROMOSOME is made up of ________ genes.
A.one
B.two
C.a few
D.large numbers of
3. CHROMOSOMES are found in the ...
A.nucleus of a cell
B.bottom of a cell
C.wall of a cell
D.cell membrane
4. DNA is...
a
very
long molecule
A.
B.a very short molecule
5. One long DNA molecule is found in each _________________.
A.nucleus
B.chloroplast
C.chromosome
6. How many chromosomes do humans have in their body cells?
A.48
B.46
C.23
7. Which sex chromosomes does a boy have? (A human male)
A.two X chromosomes
B.two Y chromosomes
C.an X and a Y
9. It's estimated that all the chromosomes together house about 19,000-20,000 individual
instructions called:
A. genome
B. DNA
C. epigenome
Wired-hair (dominant) vs. smooth-hair dog (recessive) –via Kentucky State KSU
1. What is the phenotype for dog possibilities?
2. What would HOMOZYGOUS wire-hair alleles look like (genotype)
a) SS
b) Ss
c) ss
3. Would a dog showing recessive trait of smooth-hair be homozygous or
heterozygous? Explain
4. What is the genotype of a recessive, smooth-haired dog?
a. SS
b. Ss
c. ss
Perform a punnett square of offspring of two heterozygous dogs.
5. Three different genotypes have been produced. Which ones result in wired-hair
offspring?
a. SS
b. Ss
c. ss
6. How many of the four possible offspring in the punnett square will be wirehaired?
7. Which of the genotypes will produce smooth-haired offspring?
a. SS
b. Ss
c. ss
8. What percent of four possible offspring will be wired-hair?
a. 100%
b. 75%
c. 50%
d. 25%
9. While some dogs may have the same phenotype, they may not have the same
genotype. Explain.