nov11th Flashcards
What is mosaicism?
The presence of genetically distinct cell populations within an individual, arising from mutations post-fertilization.
What is germline mosaicism?
A mutation present in reproductive cells (sperm/egg) but not in somatic cells, potentially passing to offspring without affecting the parent.
How does somatic mosaicism differ from germline mosaicism?
Somatic affects body cells, not inherited, germline affects reproductive cells and can be passed to offspring.
What is Hardy-Weinberg equilibrium?
A principle stating allele and genotype frequencies remain constant in a population under specific conditions.
How do you calculate heterozygous frequency in Hardy-Weinberg?
Use 2pq, where p and q are the allele frequencies. Example: 2(0.8)(0.2)=0.32 or 32%.
What are CpG islands?
DNA regions with high GC content and CpG dinucleotides, often near gene promoters.
What is cytosine methylation?
The addition of a methyl group to cytosine, often silencing gene expression by altering chromatin structure.
What are the components of telomerase?
TERT (protein reverse transcriptase) and TERC (RNA template for telomere extension).
What is heterochromatin?
Tightly packed chromatin, transcriptionally inactive, often enriched in repetitive DNA and CpG methylation.
What is intergenic DNA?
Regions of DNA between genes that do not overlap with any coding or noncoding gene sequences.
What are 16S rRNA genes used for?
Identifying bacteria by sequencing conserved and variable regions of the bacterial genome.
What is whole genome sequencing (WGS)?
Sequencing the entire bacterial genome to identify species and strains and study antibiotic resistance or virulence.
What is plasmid-mediated AMR?
Antimicrobial resistance genes carried on plasmids, enabling bacteria to resist multiple antibiotics.
What is a compound heterozygote?
An individual with two different mutations in the two alleles of the same gene, leading to disease in recessive disorders.
What are CpG islands’ functions?
Regulating gene expression and protecting genes from methylation-driven silencing in promoters.
How do transposons spread resistance?
They “jump” between plasmids or chromosomes, transferring resistance genes to new locations.
What is germline transmission?
Passing genetic mutations from parents to offspring through reproductive cells.
How does telomerase work?
Adds repetitive DNA sequences to the ends of chromosomes (telomeres) to protect them from degradation.
What is the role of 2pq in Hardy-Weinberg equilibrium?
It calculates the proportion of heterozygous individuals in a population under equilibrium conditions.
What is somatic mosaicism’s significance?
It leads to genetic variation within an individual’s tissues and can cause localized disorders.
What is the significance of methylation in cancer?
Abnormal methylation of CpG islands can silence tumor suppressor genes, contributing to cancer development.
What is variable expressivity?
The phenomenon where individuals with the same genotype show different degrees of a phenotype.
What is incomplete penetrance?
A genetic trait or disease does not manifest in all individuals carrying the mutation.
What is local alignment in bioinformatics?
It aligns only the regions of sequences with high similarity, ignoring the rest.
