SF.33 Genetic Websites, Variants, and Polymorphisms Flashcards
when there are identical mutations on both alleles of a specific gene
homozygote
when alleles are located at different loci within the same gene
compound heterozygote
if a variant is disease causing, it is ______
pathogenic
if a variant is not disease causing, it is ________
benign
a variant that is inherited from a biological parent
inherited variant
a variant that occurs sporadically and usually originates as an error in DNA replication
de novo variant
a _______ variant occurs when there is a change during the DNA replication that precedes meiosis
therefore, all cells have this variant in the body
germline
parents can have a germline variant only in their _____ or ______ that transmitted to their child, but they can be phenotypically _________
sperm or ovaries; phenotypically normal
a ________ variant occurs during DNA replication before mitosis
passed to next generation but NOT to all cells in the body
somatic
somatic variants are typically seen in _______ because there is more opportunities for DNA replication errors
cells that divide more
ex. skin and blood
refers to the presence of cells in a person that have different genome from the body’s other cells
can affect any type of cell but not always cause disease
mosaicism
______ mosaicism occurs when the parent has variant in sperm or oocytes because a spontaneous variant occurred in the developing testis or ovary
parent does NOT have phenotype but fetus will express phenotype
gonadal/ germline mosaicism
variants in DNA sequence that are carried by many individuals and the variant is NOT pathogenic
polymorphism
letter prefix for reference sequence: c
coding DNA strand
letter prefix for reference sequence: g
linear genomic reference sequence
letter prefix for reference sequence: m
mitochondrial DNA reference sequence
letter prefix for reference sequence: n
non-coding DNA reference sequence
letter prefix for reference sequence: o
circular genomic reference sequence
letter prefix for reference sequence: p
protein reference sequence
letter prefix for reference sequence: r
RNA reference sequence (transcript)
variant that replaces:
a purine with a purine (A to G or G to A)
a pyrimidine with a pyrimidine (C to T or T to C)
transition variant
variant that replaces a purine with a pyrimidine or vice versa
transversion variant
only nucleotide is replaced with a different nucleotide
missense variant
premature stop codon (UAA, UAG, UGA) occurs before the natural end of the gene
nonsense variant
