ERU: Inheritance + Genetic testing Flashcards
Ways to produce genetic variability? (2)
Chromosome distribution and chromosome crossing-over.
Outline the process of chromosome crossing over
- Duplicated homologs pair-up
- Spo11/ Mre11 nucleases cut DNA
- Converted to single stranded DNA able to invade each other
- Holiday junction cuts producing variability
Genetic errors examples (2)
Autosomal aneuploidy (extra chromosome) and aneuploidy affecting sex chromosomes (XXY Stallion or X0 Mare)
Law of Dominance
Dominant allele inherited
Law of Segregation
Each gamete only carries 1 allele for each gene
Law of Independent Assortment
Genes on separate chromosomes inherited separately
Incomplete dominance
No dominant or recessive. Combined result (pink flowers)
Co-dominance
Both alleles expressed (roan)
Genetic linkage
Genes close on same chromosome often inherited together
Mosaicism
Possess cells with genetic differences than other cells in body (tortoiseshell cats)
Penetrance
Proportion of indiv w/particular allele that exhibit associated phenotype
What genes does the sperm carry? (2)
- 1 of each autosome
- x/y
What does the egg carry? (3)
- 1 of each autosome
- X
- mitochondria and mitochondrial DNA
What are multi-factorial traits?
Traits from multiple genes OR combination of genetic + environmental factors
Principles of cloning
- Epithelial cells from oviduct
- Introduce DNA into empty donor egg
(3- parent child as mitochondrial DnA comes from donor)
What do PCR- based methods require?
- Template DNA
- Thermostable DNA polymerase (“Taq”)
- nucleotides
- 2 specific oligonucleotide (targets specific part) primers
Advantages and disadvantages of using PCR test
- Little DNA sample needed (also non-invasive).
- Very sensitive to contamination, can introduce mutations
What is PCR
Polymerase chain reaction. Able to amplify region of target DNA.
Uses of PCR
- Gel electrophoresis
- Detect point mutations
- Detect and identify infectious agents
- DNA fingerprinting
