Genetics Flashcards
1
Q
What are the different types of DNA mutations?
A
- Single nucleotide polymorphism (base pair substitution)
- only one amino acid in the entire protein is changed
- common SNPs are what allows people to be different
- If a single mutation happens to make a stop codon, this can cut the protein short and may be devastating
- Frame shift mutation with one base pair inserted or deleted
- the entire rest of strand will be messed up
- this is uncommon because the result would be devastating
2
Q
What are the single gene genetic disorders?
A
- Dominant- when having only one bad gene causes problems
- Recessive- when you need two defective genes to have a problem
- X-linked-
- recessive: All the Xs need to be defective; this is a bigger problem for males because they only have one X (ex. duchenne’s)
- Dominant: rare, few known- usually only seen in femalse b/c it would be fatal in males
- Y-linked- these usually result in infertility and are quickly bred out of the gene pool
3
Q
What are translocations and deletions?
A
- Translocation- genetic material from one chromosome is mistakenly put on another chromosome
- Deletion- genetic material deleted from a chromosome
4
Q
What is Aneuploidy?
A
- Nondisjunction (usually trisomy)
- Normal is to have 44 chromosomes + XX or XY
- can accidentally have three of any chromosome, but usually it is the higher numbered chromosomes because they dont carry as much information as the bigger ones and are more survivable
- Trisomy 21- downsyndrome
- Trisomy 18- Edward syndrome
- Trisomy 13- Patau
5
Q
What is Turner syndrome?
A
- Type of Aneuploidy
- Female with only one X
- only monosomy that survives to term
- these females will be infertile
- can become pregnant via IVF and HRT
- Normal intelligence, some mild cognitive problems
- Heart problems, often die around 50
- webbed necks, look pretty normal at first glance
6
Q
What is Klinefelter?
A
- A type of Aneuploidy
- Male has an extra X (47:XXY)
- infertility is most common problem, but not all are infertile
- extra DNA is more tolerable than missing DNA
- Gynecomastia
- very mild cognitive impairement
7
Q
What is polyploidy?
Explain the watermelon thing
A
- Chromosome sets that don’t equal to 2
- Ex: Partial mole
- two sperm into one egg
- usually 69:XXY or 69:XXX
- occasionally go to term but dont survive long
- Seedless Watermelon is bred to be infertile by taking a watermellon with 4 sets of chromosomes and mating it with a watermellon with 2 chromosomes
- spawn is tetraploid and infertile so it has no seeds
8
Q
Definition:
locus
A
location in the genome
9
Q
Definition:
Allele
A
one member of a pair of genes
10
Q
Definition:
Genotype
A
the genetic material
11
Q
Definition:
Phenotype
A
the physical manifestation
12
Q
Definition:
penetrance
A
the chance that phenotype follows genotype
13
Q
Definition:
Haplotype
A
alleles on a single chromosome
14
Q
Definition:
Recombinations/crossover
A
gene rearrangement between homologous chromosomes
15
Q
What are the different parts of the chromosome?
Describe the different stages of Meiosis.
A
- Parts
- P: the petit (short) arm
- Q: the long arm
- Meiosis
- Interphase S- duplication of each chromosome
- have 4 copies of each somatic chromosome
- Meiosis I (crossover)- some material from each chromosom switches over (this is how you get attributes from each parent) and then they separate homologous pairs into two separate cells
- Meiosis II- each chromosome separates and they divide again so they each have one of each chromosome (ready to mingle with somebody else’s gametes)
- Males make 4 sperm, females make 1 egg and 3 polar bodies
- Interphase S- duplication of each chromosome
16
Q
What is nondisjunction?
A
- Where a set of chromosomes doesnt split appropriately in meiosis I or meiosis II
- leads to trisomy or monosomy
- Maternal age contributes to chance of trisomy
