Question

1. Compare bacterial evolution to human evolution. How are they similar and how are they different?

2. What strategies can help prevent the evolution of antibiotic-resistant bacteria?

Answer 1

We can glean information about human history from those organisms within us in several ways. One is by using the parts of our own cells that are, in essence, microbial: our mitochondria. These organelles can be considered “extreme symbionts”: They are remnants of microorganisms that once lived free but are now integral parts of all eukaryotic (complex) cells, producing energy and regulating metabolism.

Mitochondria retain their own DNA, separate from that of the cell’s nucleus. For many types of research, this mitochondrial DNA (mtDNA) is preferable to nuclear DNA as an object of study. Unlike our nuclear DNA, it isn’t a mixture of our parents’ genetic material.

Analysis of mtDNA in the 1980s led to the conclusion that humanity originated in Africa, dating back to a common maternal ancestor somewhere around 100,000 to 200,000 years ago.

ntibiotic resistance evolves naturally via natural selection through random mutation, but it could also be engineered by applying an evolutionary stress on a population.

Once such a gene is generated, bacteria can then transfer the genetic information in a horizontal fashion (between individuals) by plasmid exchange.

If a bacterium carries several resistance genes, it is called multiresistant or, informally, a superbug.

Causes Antibiotic resistance can also be introduced artificially into a microorganism through transformation protocols.

This can be a useful way of implanting artificial genes into the microorganism.

Antibiotic resistance is a consequence of evolution via natural selection.

The antibiotic action is an environmental pressure; those bacteria which have a mutation allowing them to survive will live on to reproduce.

They will then pass this trait to their offspring, which will be a fully resistant generation.

Several studies have demonstrated that patterns of antibiotic usage greatly affect the number of resistant organisms which develop.

Overuse of broad-spectrum antibiotics, such as second- and third-generation cephalosporins, greatly hastens the development of methicillin resistance.

Other factors contributing towards resistance include incorrect diagnosis, unnecessary prescriptions, improper use of antibiotics by patients, and the use of antibiotics as livestock food additives for growth promotion.

Researchers have recently demonstrated the bacterial protein LexA may play a key role in the acquisition of bacterial mutations.

Resistant pathogens Staphylococcus aureus (colloquially known as "Staph aureus" or a Staph infection) is one of the major resistant pathogens.

3.8 billion years back emergence of the first organism	6 million years before last common grandmother of humans and chimpanzees
1.8 billion years back the emergence of Cyanobacteria, Bacteria had plenty of time to adapt to their environments and to have given rise to numerous descendant forms.	2.5 million years back evolution of genus homo in Africa
Classification of prokaryotes to Archae and eubacteria	500,000 Neanderthals evolve in Europe and the middle east
	200,000 Homo sapiens evolves in East Africa