How are genetic modifications transmitted to offspring?
incorporation of exogenous genetic recombination, or mutation (change in nucleotide order)
Functions of viral genome
has entire viral genetic info, makes infectivity, can self-replicate if nothing else present
pathogenicity vs virulence
patho - ability to cause disease virulence - degree of aggressiveness
Mutation
stable alteration on genes, constantly transmitted to offspring
Spontaneous mutation
appears normal environmental conditions without the intervention of a discernable factor
Induced mutation
occurs under the action of mutagen factors (physical or chemical)
Point mutation
alteration of a single nucleotide/codon
Errors that cause mutation
errors in nuclei acid replication, transcription/translation
2 classes of mutations
following # of affected nucleotide sequences
following type of occurrence
Revertant
mutations can be reversible→ Return to original genotype
Recombination
acquirement of exogenous genetic material thru segment exchange bw diff viruses of same host
structural homology is mandatory bw
different DNAs (not dna and rna)
Intramolecular recombination - stages
joining, breaking (polymerases) and assembling of homologous sequences
resulting recombinant
Steps of recombination (virus)
intramolecular recombination
reassortment of genome
Bacterial DNA replication
synthesis of new, identical DNA molecules
Bacterial variability
behavioral modification of bacterial cell or of its descendants
Phenotypical vs genotypical bacterial variants
pheno - adaptive changes, not hereditary, genome not affected geno - permanent genetic material change, hereditary
Transfer mechanisms of bacterial genetic material - transformation stage
bacteria accepts free DNA from another bacteria/source
Steps of transfer mechanism of bacterial genetic material
transformation
transfer mediated by bacteriophages
conjugation
Transfer mechanisms of bacterial genetic material - transduction stage
transfer of a gene fragment by a bacteriophage (donor bacteria infected, host DNA damaged, new phage particles release + infect)
Transfer mechanisms of bacterial genetic material - conjugation stage
transfer of genetic material from donor bacteria through a mating process (direct contact between the two cells), plasmids + chromosomes transferred
Essential vs accessory genes (bacteria)
essential - in bacterial chromosome accessory - extrachromosomal (plasmids, transposons + insertion elements)
Plasmids
extrachromosomal, replicate independently, genetic info not essential for bacterial life
Autonomous replication of plasmids
'rolling circle', ori is origin of replication (DNA unwinds), replication is bidirectional w/ enzymes
What is fertility factor and how is it transmitted? (plasmids)
F - gene for sexual pili transmission for F+ to F- bacteria (+ recombination)
What is R in plasmids
has genes that resist ATB
What is Col in plasmids
encoded colicines (enzymes that kill other bacteria)
Plasmids can be easily modified using
restriction enzymes (gene deletions or insertions)
Transposon
carries genes that confer new functions
Insertion elements
small, carries genes for transposition for prokaryotic cells (used in IS fingerprinting)
What do extrachromosomal elements encode?
resistance to antibacterials
synthesis of antimicrobials + colonization factors + hemolysins etc
enzymes
Detection of NA steps
harvesting
DNA/RNA extraction
gene amplification
Types of PCR
simple vs multiplex (by # genes) classic - size of amplification products must be diff real-time (qPCR)- diff fluorophores for each amplified product type qualitative - gel electrophoresis
What are safe, stable, have low toxicity and cell type specificity?
viral vectors
Advantages and disadvantages of viral vectors
adv - safe, low toxicity, stable, has cell type specificity, help identification dis - short-lived, immune response, multigene disorders