L3 Basic Concepts II Flashcards
What is an allele?
The DNA sequences at a locus of one of the two homologous chromosome
What is a genotype?
The combination of alleles at the same locus of the homologous chromosomes in a genome/cell
What is a homozygote?
When an individual has a pair of identical alleles at the locus, the genotype is homozygous
What is a heterozygote?
When there are two different alleles at the same locus, the genotype is heterozygous
What is hemizygous/hemizygote?
One allele present while another allele is missing
also heterozygous
What is Mendel’s Law?
Each of the parents passes a randomly selected allele (one of the two homologous chromosomes) to the offspring
What is the most common DNA sequence variation?
Single nucleotide polymorphisms
a single nucleotide is changed to another
What is a cSNP?
SNP in the coding region
What is a non-synonymous SNP?
missense SNP, nonsense SNP
changing amino acid in the protein
What is a missense SNP?
amino acid substitution that could either lead to a gain or loss of function for the protein depending on what amino acid it changes to
What is a nonsense SNP?
amino acid changes to stop codon (normally lead to loss of function)
What is a synonymous SNP?
silent SNP
Does not change amino acids, usually does not change gene/protein function.
What is copy number variation (CNV)?
A DNA region has 0-n copies in a population
What is an Indel (insertion/deletion)?
Nucleotide(s) added or removed from a locus
Unless the indel is of 3 nucleotides, what will happen?
- Frameshift
- frameshift of the open reading frame leads to truncated protein for degradation (loss of function)
When “c.” is in front of the nomenclature, which sequence are you looking at?
coding DNA sequence
When “p.” is in front of the nomenclature, which sequence are you looking at?
protein position
What does *1A indicate?
No change
What does *2D indicate?
splicing defect (loss of function)
What does *3A indicate?
nonsense (Stop codon) (loss of function)
What does *17 indicate?
missense (point mutation) `
