Lecture 18: Genetics Flashcards
How many copies of genes do we inherit? And from whom?
2 copies, from you biological mother and father.
What does the study of genetics entail?
Inheritance
What does the study genetics consider?
phenotype and genotype
What are different versions of a gene called?
Alleles
What are the different types of genotype?
Homozygous and heterozygous
Define homozygous and heterozygous.
- Homozygous: both copies are the same
- Heterozygous: both copies are different
What can cause complications with gene expression?
The production of a protein by an allele that overpowers the other allele.
What is the name of an allele that can overpower another allele?
The dominant allele.
What is the name of an allele that can be overpowered by another allele?
The recessive allele.
How can one study inheritance easily?
Over many generations of a species.
What are organisms called that are typically homozygous?
True breeding organisms
What must a heterozygote always have?
A dominant phenotype.
How many alleles do humans have? Explain why?
-two alleles, because they are diploid.
Explain the type of genotype that someone with Rr has.
-A heterozygous genotype
Explain the type of genotype that someone with RR has
-A dominant homozygous
Explain the type of genotype that someone with rr has
-A recessive homozygous
What is used to make predictions?
The Punnett Squares.
Describe how Punnet squares are used?
- Indicate which each parent can produce
- Create all possible combinations of offspring
- Predict the probability that two parents have a certain type of offspring.
Define test cross.
A test cross involves breeding and unknown specimen with a recessive individual. And the ratio of offspring tells you the unknown genotype of the other parent.
What genotype carries a recessive disease?
The heterozygous genotype that carries the disease
What genotype has a recessive disease?
The recessive homozygous genotype that has the disease.
What type of disease is cystic fibrosis?
A recessive disease.
If two parents have a recessive disease, what % chance will the child have this disease as well?
100%
Can cystic fibrosis can be verified with genetics? if so, when?
Yes, at a fetal stage.
How fraction of people carry the cystic fibrosis recessive disease?
1/25
How can genetic diseases be sexist?
since women have two X chromosomes and men only have one X chromosomes, any recessive disease carried through the X chromosomes will be expressed in the male phenotype. For a girl to inherit a recessive disease on the X chromosome, her mother and father must have it.
What are alleles that are equally expressed (neither is dominant over the other) called? Give an example
Co-dominant alleles.
An example is X and Y sex chromosomes.
When a trait is dominant or recessive on the X chromosomes, what is the particular inheritance patterns called?
Sex-linked trait.
What is the most practical method in which to track human inheritance over many generations?
Pedigree charts.
Why shouldn’t you reproduce with relatives?
It helps propagate genetic mistakes
In gene therapy, what is the difference between In vivo and Ex vivo?
- In vivo: the genes are transferred directly into cells while still in the patient (internal)
- Ex vivo: the cells are taken from the patients and the genes of the cells are modified in a lab (external) then the cells are transferred back into the patient.
