exp 4 Flashcards
(49 cards)
where can small scale mutations occur
coding sequences
noncoding portions
in regions between genes
When base substitutions occur within the coding regions, what are the three possible effects
silent mutations- no amino acid change
missense mutations- amino acid change
nonsense mutations- stop codons
what can insertions or deletions do within a coding sequence?
they can either cause the gain or loss of a codon
or cause a frameshift mutation
if a mutation does not occur within the coding sequence of a gene, will it still affect the expression of the gene?
it can, if it occurs at the promoter, at a regulatory element, an untranslated region, or a splice site
what is a SNP?
it is a base substituion within the genoe
what do SNPS serve as?
they serve as molecular markers and are used to index the variation that exists between inidviduals
why are SNPs important?
they can be genetically linked to a gene directly involve in a disease
do SNPS cause diseases
no, they but they may exist nearby a gene that is involved in the disease and can be used as a predictor
what is the goal of a GWAS
it is used to identify SNPS that may be predictors of disease
how do GWAS work
it is used to determine whether a particular SNP is statistically found more often in individuals with the disease
what is a haplotype?
it is a set of closely linked genetic markers or DNA variations on a chromosome that tend to be inherited together
what is newborn screening
it is a heel prick test that is used within 24-48 hours after birth to analyze for disorders
what is fetal DNA screening
it is analysis of fetal DNA prior to birth
what is preimplantation genetic diagnosis
it is genetic profiling of embryos where cells from early cleavage stage embryos can be removed and analyzed
embryos without disorders can be selected for implantation
how do microarray chip methods work
immobilzed known DNA is fixed to the array
patient and control DNA are fluorescently labeled and they will hybridize with the array
the pattern of fluorescence will be used to detect abnormalities
what is predictive testing
it is testing for individuals who are presymptomatic and may be tested for the risk of developing a condition, but these tests carry a degree of uncertainty
what are the drawbacks of DTC
they are not the most secure for privacy and the companies do not test for all variants, they only test the most common so they cannot be entirely predictive
what is the purpose of cytogenetics
it is the study of chromosomal organization and allows us to determine large scale chromosomal mutations
how will organisms that are closely related be visualized chromosomally?
they will share similar chromosome makeups in number, size, shape, and bands
how are karyotypes prepared
cells are induced to enter mitosis by adding a mitogenic agent and then will be arrested in metaphase
what is the purpose of colchicine in karyotype preparation
it is added to the culture and binds to microtubule-forming proteins that will prevent formation of the spindle apparatus, this arrests metaphase
why do we arrest metaphase
chromosomes are maximally condensed and easily seen at this point
what is the purpose of karytotyping fetal cells when the mother is older
we can use this to detect mutations in fetal cells and it is important in older mothers as there is a higher risk for nondisjunction event mutations
what are the 4 variations of centromere position
metacentric, submetacentric, acrocentric, and telocentric
