March 22 - Genetics Flashcards
Enhancers
bind activator proteins that facilitate bending of DNA; bending allows the activator proteins to interact with transcription factors and RNA polymerase. Increases rate of transcription. Can be upstream, downstream, or within introns
Leber hereditary optic neuropathy inheritance
mitochondrial
Cri-du-chat
Caused by 5p deletion. PResents with weak cry, hypotonia, failure to thrive, developmental delay, microcephaly, low set ears, hypertelorism, broad nasal bridge
Quad screen in trisomy 21
Decreased fetal proteins: estriol and AFP
Increased beta-hCG and inhibin A - placental hormones
Fragile X
Increased CGG repeats on FMR1 gene causes hypermethylation of cytosine causing FMR1 inactivation
Cardiac manifestations of digeorge
tetralogy of fallot, truncus arteriosus
Angelman syndrome
Caused by maternal gene deletion + paternal genes silenced
Microcephaly, ataxia, hand flapping, frequent laughter
Tuberous sclerosis
Caused by defect in tumor suppressor genes TSC1 and TSC2
Cutaneous angiofibromas, brain hamartomas, cardiac rhabdomyomas
Aromatase deficiency
Autosomal recessive.
Female: In female, high androgens and low estrogen results in virilization at birth. Maternal hirsutism in pregnancy distinguishes from 21 hydroxylase def. In puberty, low estrogen causes primary amenorrhea, osteoporosis, talls tature.
Male: Osteoprosis and tall stature without genital abnormalities
Pleiotrophy
1 gene mutation causes seemingly unrelated phenotypes in multiple organs
Segmented viruses
Orthomyxoviruses, reoviruses, bunyaviruses, arenaviruses
Recombination
Crossing over between two dsDNA
Phenotypic mixing
Coinfection with two viral strains. Progeny have parental genome from one strain, capsid from other
Expression cloning
Type of cloning where signals necessary for transcription and translation included in cloned DNA so that bacteria produce a lot of the protein of interest
DNA probes
used for TFs, steroids, thyroid hormone, vit D receptor, retinoic acid receptor, transcription and replication proteins
Primary and secondary oocytes: stages of arrest
Primary oocytes arrested in prophase I until ovulation
Secondary oocytes arrested in metaphase II until fertilization
Histones
H2 through H4 make up histone core. Negatively charged DNA wraps twice around positively charged histone cores. H1 on outside of histone core binds to linker segments of DNA between nucleosomes, facilitating packaging of nucleosomes into compact structures
ras
G protein that cycles betwen active ras-GTP and inactice ras-GDP
Tay Sachs
def of hexosaminidase A leading to accumulation of GM2 No HSM
Gaucher disease
def of beta-glucocerebrosidase leading to accumulation of glucocerebroside aseptic necrosis of femur and HSM
Fabry disease
def of alpha-galactosidase A leading to accumulation of trihexoside
peripheral neuropathy, CV and renal disease
X-linked recessive
Niemann pick
def of sphingomyelinase leading to accumulation of sphingomyelin progressive neurodegeneration, cherry red spot, HSM
Lac operon
expression requires cAMP and lactose
- lactose binds repressory removing it from operator
- cAMP is marker of low glucose and binds to receptor to form cAMP activating protein which facilitates RNA polymerase binding to promotor
lactose increases expression, glucose inhibits expression
Myotonic dystrophy type I and II
Type I presents in childhood and includes intellectual disability. Trinucleotide repeat
Type II presents in adulthood with proximal weakness and delayed muscle relaxation. Associated with cataracts and glucose intolerance. Repeat exp (CCTG) of CNBP gene
