Question

Karl Klose, in his TED talk, explains the three methods of horizontal transfer. He says that they are “the funeral grab”, bacterial sex, and the viral pass. Which metaphor goes with which mechanism of genetic transfer? Explain, for each one, why this metaphor makes sense.

Answer 1

Funeral grab-We get our genes from our parents, and what we're born with we're stuck with for our whole lives. Bacteria, however, like to do things a little differently. They don't need to use traditional reproduction to pass their genes along, they can use something called a "horizontal gene" transfer to swap genetic information like you swap Pokémon cards. And one of the best way bacteria acquire new genes is to loot their neighbor's body when they degrade and die. This process is known as "transformation", although some pathologists have dubbed it "the funeral grab". It happens when bacteria are in a special physiological state called competence, during which they can scavenge bits of foreign DNA from their environment.

Bacterial sex- DNA transfer is considered bacterial sex, but the transfer is not parallel to processes that we associate with sex in higher organisms. How frequently this occurs in dental plaque is not clear, but evidence suggests that it affects a number of the major genera present. It has been estimated that new sequences in genomes established through horizontal gene transfer can constitute up to 30% of bacterial genomes. Gene transfer can be both inter- and intrageneric, and it can also affect transient organisms. The transferred DNA can be integrated or recombined in the recipient's chromosome or remain as an extrachromosomal inheritable element. This can make dental plaque a reservoir for antimicrobial resistance genes.

Viral pass-Horizontal transfer (HT) of genetic material, mainly transposable elements, is increasingly recognized as an important factor shaping eukaryote genome.It has been proposed that such transfers may be facilitated by viruses, because they typically inject their genomes into host cells to replicate and they can be horizontally transmitted between their hosts. Recent evidence from high throughput sequencing of viral populations and paleovirology shows that both virus-to-host and host-to-virus gene flow can be common in a variety of eukaryote lineages.