genetics terminology + terminology Flashcards
age of onset is earlier and earlier presentation in successive generations or severity of disease worsens with successive generations
anticipation
diseases with anticipation
Huntington disease: trinucleotide repeats expand with successive generation
how often a genotype causes a particular phenotype
not all with mutant genotype show mutant phenotype
mutation appears to skip generations but still present
incomplete penetrance (may not get cancer)
2 alleles
neither is dominant
codominance (ABO blood type)
severity of phenotype varies from one individual to another
variable expression (tuberous sclerosis - different disease severity)
single gene has more than one effect on phenotype
pleiotropy (PKU: ID, light skin, musty body odor)
mutations at different loci can produce the same phenotype
locus heterogeneity: marfanoid body habitus in: marfan syndrome MEN-2B homocysteinuria
cells in body have different genetic makeup (lose genetic information during mitosis)
mosaicism
phenotype differences depend on whether mutation comes from mother’s or father’s genetic material (some genes normally inactivate one of the sex’s chromosome)
imprinting:
both caused by deletion of gene on chrom 15
Prader-willi syndrome
angelman syndrome
deletion of gene on chrom 15
deletion of assigned active allele: paternal
Prader-Willi syndrome = Paternal
deletion of gene on chrom 15
deletion of assigned active allele: maternal
angelMan syndrome = Maternal
presents in infancy: hypotonia, poor feeding, almond-shaped eyes, downward turned mouth
symptoms: hyperphagia, obesity, short stature (partial GH deficiency), ID, behavior: tantrum, skin-picking, OCD, hypogonadotropic hyopgonadism → genital hypoplasia,childhood OP, delayed menarche
Prader-Willi syndrome = Paternal
diagnosis of prader-willi syndrome
FISH
ID
seizure
ataxia
inappropriate laughter
Angelman syndrome
amplify a sequence of DNA in 3 steps:
1) DNA denaturation: heat DNA → 2 strands separate
2) annealing: cool DNA + add DNA primers (in vivo is RNA primer) that bind to sequence to be amplified
3) elongation: DNA poly replicates sequence after the primer
PCR
sort + separate PCR DNA fragments based on size
gel electrophoresis
put PCR products in wells
run current through gel: DNA travels toward + electrode (anode)
smaller molecules travel further
gel electrophoresis
gel to separate protein particles
protein electrophoresis
1) separated DNA by size with gel electrophoresis
2) take DNA sample and put on filter and denature DNA to separate strands → labeled DNA probe (radioactive or fluorescent) binds/identifies DNA sample
southern blot
Down south = DNA
DNA sample
DNA probe
use DNA probe to identify RNA sample
northern blot
Rude yankees = RNA
RNA sample
DNA probe
use antibody probe to identify protein sample
western blot
Beef: protein
protein sample
antibody probe
use oligonucleotide probe to identify DNA binding proteins sample (TF)
southwestern blot
analyze patient’s blood to determine if ANTIGEN is present in blood using antibodies (in wells of a plate)
anti-antigen antibodies added (an enzyme substrate) and bind to antigen →emit a color which detects the antigens presence
direct ELISA test
analyze patient’s blood to determine if ANTIBODIES are present in blood using antigen (in wells of plate)
anti-antibody antibodies added (an enzyme substrate) and bind to antibodies → emit a color which detects the antigens presence
indirect ELISA test
HIV antibodies in blood: ELISA screening test
if +: confirmatory test is western bloot
use DNA or RNA fluorescent probe to bind to gene of interest
no fluorescence = deleted gene
FISH
cloning recombinant DNA molecules
use mRNA that corresponds to gene to be cloned
use reverse transcriptase to turn mRNA → complementary DNA (cDNA) (only contains EXONS since from mRNA = coding region)
insert cDNA into bacterial plasmid: replicate cDNA as bacteria replicates
cloning
delete gene from mouse’s genome: knock-out mouse
insert gene: knock in mouse
insert gene randomly: constitutive insertion
targeted insertion: conditional insertion
modifying gene expression
metaphase chromosomes (condensed) diagnose chromsomal imbalances by gross architecture
karyotyping
trisomy or sex-chromosome disorders
amniotic fluid test to diagnose trisomy 21 in utero
karyotyping
