T5M1- Genetic Variation Flashcards
define tandem repeats
occur in DNA when a pattern of one or more nucleotides is repeated and the repetitions are directly adjacent to each other.
when is there no observed effect in variations
when occurs in non coding regions
define DNA polymorphisms
presence of two or more variant forms of a specific DNA sequence that can occur among different individuals or populations
how are DNA polymorphisms used in mapping
allow assembly of high density genetic maps
- referred to as DNA markers
what can DNA polymorphisms be used for
identify individuals or show relatedness
how are DNA polymorphisms detectable
microarray analysis, PCR blot or DNA sequencing
what is the most common type of genetic variation
single nucleotide polymorphisms (SNP)
what are SNPs
change due to single nucleotide base change or substitution in sequence
where are SNPs found
both coding and non coding regions
when can SNP be a marker?
if found near a particular gene
what happens if a SNP is linked to a gene of interest?
its passed on with the gene
what are attached to glass chips during DNA microanalysis
oligonucleotides
what are oligonucleotides
short single strands of synthetic DNA or RNA
how are DNA strands identified in DNA microarray
fragments of single stranded fluorescent DNA is hybridized into chip
how to tell if someone is homozygous or heterozygous for a SNP using DNA microarray
due to known position of probes in chips, the short complementary DNA attach and can be tracked to identify SNP to see if homo or heterozygous
how are tandem repeats positioned
adjacent to one another
how are tandem repeats identified
PCR and gel electrophoresis
define genotype
representation of pair of alleles carried by a person
define phenotype
cell or body’s interpretation of genotype
what is different about sickle cell anemia red blood cells
assume sickle shape compared to normal biconcave, round shape
why are sickle red blood cells dangerous
oxygen is not carried efficiently- cannot smoothly stack and block fine capillaries
what are some symptoms of sickle cell anemia
anemia and acute pain
which chromosome is responsible for beta globin protein
chromosome 11
which allele codes for functional red blood cells
homozygous HbA allele
which allele codes for sickle red blood cells
homozygous HbS
what causes HbS genotype
mutation or SNP during protein coding
what is the acute pain in sickle cell anemia patients due to
damage of organs and tissues
what is the acute pain in sickle cell anemia patients due to
damage of organs and tissues
what happens if someone has HbA/HbS genotype
no symptoms of sickle cell anemia- enough normal hemoglobin is produced to overcome effect
what advantage do HbS/HbA individuals have?
resistance to malaria
two polymorphisms that contribute to genetic variation
SNP and variable number
how can copy number variation be identified
based on fluorescent intensities
correlation between low starch diets and AMY1 gene
fewer gene copies
are SNPs always located within genes
no, can be outside as well
define linked SNPs
located outside genes and do not effect protein function
- can still serve as markers
define causative SNPs
affect the way a protein functions correlating with a disease
- in coding or regulatory regions
