Evolution And Medicine

Question 0

Antibiotics

Answer 0

Immune system exposed to dead viruses, recognize viral proteins as foreign and mounts a response then remembers structure, can respond immediately to later infection, goal to kill off bacteria

Question 1

Hemagglutinin

Answer 1

Initiates infection of influenza A by binding to host cell, is recognized, attacked and remembered by host immune system, given strain only persists if it has a new supply if hosts who have not seen the strain before (new mutations have increased survival)

Question 2

Behavioral fever

Answer 2

Responsive fever as a result of infection, theoretically to help body fight off infection, behavior to heat up own body

Question 3

Substitutions in influenza A hemagglutinin gene

Answer 3

Most of gene silent > non-synonymous which suggests neutral evolution by genetic drift

Question 4

Substitutions in antigenic portion of influenza A hemagglutinin gene

Answer 4

Non-synonymous > silent suggests natural selection for amino acid changes (favoring), human immune system exerts selection on viral hemagglutinin gene

Question 5

Evolution affecting vaccines

Answer 5

Strains diversely very rapidly through nucleotide substitutions in the hemagglutinin gene but most new strains go extinct and don’t persist but the longest living change the most and more rapidly, vaccines prepared in advance and thus how do you choose which mutations to put in the vaccine? (Most recent mutations)

Question 6

Antibiotic resistance decline as antibiotic use declines

Answer 6

Bacteria evolve resistance to antibiotics, when antibiotic use decline resistance declines (suggests resistance is costly for bacteria and is deleterious in absence of antibiotics) increase in resistance continue even with antibiotic decline possible (suggests that a mutation is compensations for or eliminates cost of resistance -no longer deleterious)

Question 7

Guidelines to limit bacterial evolution and spread of resistance

Answer 7

Minimize infections (wash food/hands), minimize unnecessary antibiotic use (antibacterial soaps, antibiotics when not needed - viral infections or wrong infection species), kill all bacteria before resistance evolves (use full course of antibiotics, don’t save for later), isolate patients infected with resistant bacteria

Question 8

Cells within tissues = individuals within population

Answer 8

Each make up the other, connection to cancer (mutations cause cancer cells to divide more rapidly than other cells (have greater fitness) which can increase in frequency and take over tissues (like natural selection in populations of cells), metastasis is like the founder effect where newly founded tumors/populations expected to have fewer alleles than older tumors and can determine the origin of the cancer from that)

Question 9

Tumors evolving populations of cells

Answer 9

Mutations in previously normal cells that have unregulated division, higher fitness in unregulated division (reproduce quicker and take more space), idea of founder effect with metastasis - few cells from tumor move to other parts of body and grow there

Question 10

Cancer cells

Answer 10

Analogous to deleterious mutations

Question 11

Allelic diversity and tumor

Answer 11

Fewer mutations mean older and likely starter, can estimate age of tumor based on genetic diversity in tumor (# of different alleles for a given gene)

Question 12

Lactose intolerance

Answer 12

Response to moderate diet, was a good source of nutrients and proteins in older societies, type of society, not enough time to evolve

Question 13

High hypertension rates in African-Americans

Answer 13

Hypothesis 1: gradual selection for salt retention in historically hot environment (lower salt intake historically and salt lost through swearing in hot environments - slow selection, hot environments may have selected for kidneys with efficient salt retention - more likely to develop high boos pressure with moderate diet)
Hypothesis 2: strong selection during slave trade (potential for strong selection during salve trade - rapid selection, unbalance salt loss due to diarrhea, vomiting and sweating increase death rate)

Question 14

Breast cancer in North American women

Answer 14

1/8 have breast cancer, may be related to high rates of menstrual cycling (more menstrual cycles = greater risk since post-ovulatory hormones stimulate cell division and there is a greater chance for cancer mutations), Dogon women of West Africa have a 1/12 risk, fewer contraceptives - pregnant and lactating more so fewer menstrual cycles

Question 15

Fever during infections

Answer 15

Hypothesis 1: fever is a manipulation of the host by the pathogen (benefits pathogen reproduction to increase host temperature, fever reducing drugs might help recovery)
Hypothesis 2: fever is an adaptive defense against pathogens (slows pathogen reproduction or increases immune response, fever reducing drugs might inhibit recovery)

Question 16

Desert iguanas

Answer 16

Supports fever being an adaptive defense (h2) since they behaviorally thermoregulate to induce fever, iguanas with fever more likely to survive infection, reducing fever with aspirin results in greater deaths

Question 17

Improved survival rates of rats infected with bacteria

Answer 17

High metabolism of fever beneficial to fever not the hight temperature, increased survival rates with higher metabolism

Question 18

Anti-fever medication in humans with cold

Answer 18

Cause more stuffy noses and reduce antivirus antibodies

Question 19

Continue taking anti-fever medication?

Answer 19

Yes - fever may only work against certain pathogens and not others if its an adaptive defense, medications alleviate symptoms (may be worth the cost of a slightly diminished immune system), high fever has potential to be costly (depletion if nutritional reserves, neurological and other tissue damage)