genetics essays

Question 1

thermal liability of purine-N- glycosidic bond

Answer 1

depurination

Question 2

depurination

Answer 2

thermal liability of purine-N- glycosidic bond

Question 3

VDJ

Answer 3

Variable diversity joining

t cells

immune system

Question 4

NER recognition

Answer 4

XPE and XPC

Question 5

helix uncoilling NER

Answer 5

tfiih

Question 6

5’ cleavage NER

Answer 6

XPF

Question 7

3’ cleavage NER

Answer 7

XPG

Question 8

what does MUTs scan for

Answer 8

adenosine methylation in GATC sequency.

GATC also acts as the site of exonuclease activity of Mut H

Question 9

DNA infidelity fixed by

Answer 9

Missmatch repair

Question 10

strand invasion steps

Answer 10

resection by exonuclease to make a 3’ overhang

rad 51 joins with RAP- strand invasion protein

D loop forms with homologous chromosome. D loops forms Holliday junction

strand extrension and continued migration.

crossover is common at sites of holiday crossovers.

Question 11

strands in NHEJ brought together by

Answer 11

DNA protein kinase and protein KU

polymerase involved in synthesising 3’ overhangs

can lose nucleotides

Question 12

mutation in BRCA to cause PARP resistance

Answer 12

53BP1

Question 13

BIOMARKER FOR POOR ner

Answer 13

ercc1

cisplatin sensitivity

Question 14

biomarker for DSB

Answer 14

Rad51

Question 15

actionable incidental finding statistic

Answer 15

Yang 10% had actionable incidental findings

Question 16

causes of mutational signiture

Answer 16

DNA replication infidelity
Exogenous and endogenous carcinogen exposure
DNA repair
enzymatic editing

Question 17

sanger sequencing

Answer 17

dye-chain termination

Dye-terminator sequencing utilizes labelling of the chain terminator ddNTPs, which permits sequencing in a single reaction, rather than four reactions as in the labelled-primer method. In dye-terminator sequencing, each of the four dideoxynucleotide chain terminators is labelled with fluorescent dyes, each of which emit light at different wavelengths.

Question 18

difference between dNTP and ddNTP

Answer 18

ddNTP lack a -OH group so cannot form phosphodiester bond

Question 19

signiture 7

Answer 19

UV

pyrimidine pyrimidine photodimers

cc:gg > TT:AA

ner

Question 20

tobacco bulky adduct

Answer 20

benz(o) pyrine

Question 21

CDCV Chrons

Answer 21

IL23R chrons 93% present in the population

Question 22

CDCV alzeihmers

Answer 22

APOE4 gene-

Question 23

Arguments for CDRV

Answer 23

online mendelian inheritance in man

negatively selected for => rare

BRCA
CF

EXPRESSIVITY MONITERED BY MODIFIER GENES AND EPIGENETICAS

Question 24

arguments against CDRV

Answer 24

MISSING HERITIBILITY WHEN LOOKED AT UNDER GWAS STUDIES.

schizophrenia genetics- the sibling risk is generally not what would be hypothesised from a single risk causing allele. familial clustering?

GWAS associations are consistent across populations. If rare variants are recently derived relative to the common variants, then they should be at different frequencies in Caucasians and Asians

Question 25

other name for the CDCV model

Answer 25

infinitesimal

Question 26

quantitative trait locus

Answer 26

GWAS has failed to identify varients with such high odds ratios as in QTL

Question 27

Absence of blending inheritance

Answer 27

phenotypes are often not continuous

Certain features such as the shape of the nose, location of the cheek bones, or curve of the lips, run strongly in families, appearing in distant relatives in patterns that are suggestive of large genetic effects.

Question 28

CDCV Fisher

Answer 28

combination

Question 29

CDCV reich and lander

Answer 29

spectrum

Question 30

CDCV Provine

Answer 30

The origins of theoretical population genetics

1970s

held up

Question 31

familial clustering expresivity influences

Answer 31

segregation

environment

Question 32

complications to CDCV

Answer 32

allelic heterogeneity- one locus, many variants, one phenotype eg CF

modifier genes- haldane

imprinting
epigenetics, ivf, Uniparental disomy (prader willi)