Question

Does anyone know how to solve this question? I am so lost. Thank you!

You are studying the source of new virus that has recently infected humans. You suspect that the virus was transferred from other primates (they exhibit a similar infection), specifically chimpanzees, gorillas, or orangutans. You sample blood from several infected humans and sequence some viral genes. You then build a phylogenetic tree with the human sequences and all the known strains from each primate. Draw a hypothetical phylogenetic tree that would suggest that the virus came from gorillas, and this transfer occurred twice independently. Label chimp sequences (c), gorilla (g), orangutans (o), and humans (h).

Answer 1

The source of new virus that has recently infected the human race is AIDS and HIV Virus.

this infection is identified chimpanzees in southern Cameroon but had their origins in western lowland gorillas. Thus, both chimpanzees and gorillas harbor viruses that are capable of crossing the species barrier to humans and causing major disease outbreaks.

AIDS is caused by HIV-1 and HIV-2, which are derived from a clade of lentiviruses [simian immunodeficiency viruses (SIVs)] found naturally in more than 40 species of nonhuman primates in sub-Saharan Africa . These SIVs mostly fall into host-specific clades, but they have occasionally jumped species and spread successfully in new hosts. Of particular interest, chimpanzees (Pan troglodytes) acquired two distinct lineages of SIV from two different monkey species; all known strains of chimpanzee SIV (SIVcpz) are derived from a hybrid formed by recombination between these two viruses . The spread of this virus in chimpanzees appears to have occurred comparatively recently, because only two closely related subspecies in Central Africa are infected, whereas two other subspecies are not (4–8). Subsequently, strains of SIVcpz from one chimpanzee subspecies (Pan troglodytes troglodytes) have been subject to further transmission both to humans, leading to HIV-1, and to western gorillas (Gorilla gorilla), giving rise to gorilla SIV. The limited number of strains of SIVgor characterized so far form a single clade, but HIV-1 strains fall into four phylogenetically distinct groups, each of which must reflect a separate cross-species transmission from apes . These four zoonotic events have had very different outcomes. One gave rise to group M, the cause of the AIDS pandemic, which has infected more than 40 million people and spread across Africa and throughout the rest of the world. At the other extreme, group N and P viruses have only been found in small numbers of individuals from Cameroon: group N in fewer than 20 individuals and group P in only two individuals. Group O, although not nearly as prevalent as group M, has nonetheless caused a substantial epidemic. Although largely restricted to west central Africa, group O viruses have spread through Cameroon, Gabon, Nigeria, and other neighboring countries, and are estimated to have infected about 100,000 individuals .

As we have observed by results obtained from laboratory-

we concluded that the virus came from gorillas, and this transfer occurred twice independently.

As a result we are able to draw a phylogenetic tree -

	GORILLA CHIMPANZEE       ORANGUTANS                      HUMAN