nov11th

Question 1

What is mosaicism?

Answer 1

The presence of genetically distinct cell populations within an individual, arising from mutations post-fertilization.

Question 2

What is germline mosaicism?

Answer 2

A mutation present in reproductive cells (sperm/egg) but not in somatic cells, potentially passing to offspring without affecting the parent.

Question 3

How does somatic mosaicism differ from germline mosaicism?

Answer 3

Somatic affects body cells, not inherited, germline affects reproductive cells and can be passed to offspring.

Question 4

What is Hardy-Weinberg equilibrium?

Answer 4

A principle stating allele and genotype frequencies remain constant in a population under specific conditions.

Question 5

How do you calculate heterozygous frequency in Hardy-Weinberg?

Answer 5

Use 2pq, where p and q are the allele frequencies. Example: 2(0.8)(0.2)=0.32 or 32%.

Question 6

What are CpG islands?

Answer 6

DNA regions with high GC content and CpG dinucleotides, often near gene promoters.

Question 7

What is cytosine methylation?

Answer 7

The addition of a methyl group to cytosine, often silencing gene expression by altering chromatin structure.

Question 8

What are the components of telomerase?

Answer 8

TERT (protein reverse transcriptase) and TERC (RNA template for telomere extension).

Question 9

What is heterochromatin?

Answer 9

Tightly packed chromatin, transcriptionally inactive, often enriched in repetitive DNA and CpG methylation.

Question 10

What is intergenic DNA?

Answer 10

Regions of DNA between genes that do not overlap with any coding or noncoding gene sequences.

Question 11

What are 16S rRNA genes used for?

Answer 11

Identifying bacteria by sequencing conserved and variable regions of the bacterial genome.

Question 12

What is whole genome sequencing (WGS)?

Answer 12

Sequencing the entire bacterial genome to identify species and strains and study antibiotic resistance or virulence.

Question 13

What is plasmid-mediated AMR?

Answer 13

Antimicrobial resistance genes carried on plasmids, enabling bacteria to resist multiple antibiotics.

Question 14

What is a compound heterozygote?

Answer 14

An individual with two different mutations in the two alleles of the same gene, leading to disease in recessive disorders.

Question 15

What are CpG islands’ functions?

Answer 15

Regulating gene expression and protecting genes from methylation-driven silencing in promoters.

Question 16

How do transposons spread resistance?

Answer 16

They “jump” between plasmids or chromosomes, transferring resistance genes to new locations.

Question 17

What is germline transmission?

Answer 17

Passing genetic mutations from parents to offspring through reproductive cells.

Question 18

How does telomerase work?

Answer 18

Adds repetitive DNA sequences to the ends of chromosomes (telomeres) to protect them from degradation.

Question 19

What is the role of 2pq in Hardy-Weinberg equilibrium?

Answer 19

It calculates the proportion of heterozygous individuals in a population under equilibrium conditions.

Question 20

What is somatic mosaicism’s significance?

Answer 20

It leads to genetic variation within an individual’s tissues and can cause localized disorders.

Question 21

What is the significance of methylation in cancer?

Answer 21

Abnormal methylation of CpG islands can silence tumor suppressor genes, contributing to cancer development.

Question 22

What is variable expressivity?

Answer 22

The phenomenon where individuals with the same genotype show different degrees of a phenotype.

Question 23

What is incomplete penetrance?

Answer 23

A genetic trait or disease does not manifest in all individuals carrying the mutation.

Question 24

What is local alignment in bioinformatics?

Answer 24

It aligns only the regions of sequences with high similarity, ignoring the rest.