Read the Guilty dentist information. Then use your understanding to answer the following question:What was the conclusion? Science ToolkitThe Guilty DentistWhile biologists use the study of evolutionary relationshipsmainly to build evolutionary trees of the world's organisms,scientists are finding wider and wider uses for evolutionarytrees. Scientists have even used evolutionary trees to solve the mysteryof whether a dentist infected his patients with HIV, the virus that causesacquired immunodeficiency syndrome (AIDS) in humans.The dentist, who was himself infected with HIV, had been working, asusual, with his patients. Then some of his patients began turning up HIV-positive. Against a backdrop of increasing public controversy over whetherhealth care workers with HIV pose a risk to their patients, many peoplewanted to know: had this dentist transmitted the deadly virus to hispatients? Adding confusion to the situation was the fact that some of theinfected patients had lifestyles orhabits that put them at risk forHIV infection by other means.Those on both sides of the issue-some saying the dentist should notbe blamed, others saying he was athreat-argued heatedly withoutresolution.In order to answer the question,researchers took advantage of theobservation that HIV's geneticmaterial, like that of most viruses,evolves quickly, resulting in manydifferent but closely related strainsof HIV. The researchers createdan evolutionary tree of the viralstrains found in the dentist, in eachof the infected patients, and in localpeople who were also infected withHIV but were not patients of thedentist. If the dentist had infectedAfrican Patientperson XPatient Local non-Y patient 1his patients, then the strains of HIV found in his patients should be moreclosely related to his strain and less closely related to the strains fromother infected people.The results showed that some of the dentist's patients probably wereinfected by him and that some probably were not. Two patients, X andY, who could have been exposed to HIV as a result of their lifestyles orhabits, had HIV strains that were not closely related to the dentist'sstrain. However, five other patients-A, B, C, D, and E-were carryingstrains of the virus very closely related to the strain in the dentist.Moreover, those people were not at risk of contracting HIV by othermeans. So the scientists concluded that, at least in the case of these fivepatients, the dentist had infected them with his strain of the virus.Local non-patient 2Local non- Local non-patient 3patient 4Patient Patient Patient DentistACAn Evolutionary Tree Solves the WhodunitBy examining the evolutionary relationships among the strains of HIV found in a number of infected people,including a dentist and his infected patients, researchers were able to solve the mystery of how hispatients were likely to have been infected.unearthed in 1923 the idea that it might be sittin las lushes that lettPatient Patient

HIV stands for human immuno deficiency virus which is a retro virus responsible for causing AIDS. It…

Science Toolkit The Guilty Dentist hile biologists use the study of evolutionary relationships mainly to build evolutionary trees of the world's organisms, scientists are finding wider and wider uses for evolutionary entists have even used evolutionary trees to solve the mystery ra dentist infected his patients with HIV, the virus that causes immunodeficiency syndrome (AIDS) in humans. ntist, who was himself infected with HIV, had been working, as h his patients. Then some of his patients began turning up HIV- gainst a backdrop of increasing public controversy over whether e workers with HIV pose a risk to their patients, many people know: had this dentist transmitted the deadly virus to his Adding confusion to the situation was the fact that some of the atients had lifestyles or at put them at risk for tion by other means. oth sides of the issue- g the dentist should not others saying he was a gued heatedly without to answer the question, s took advantage of the on that HIV's genetic ce that of most viruses, ckly, resulting in many t closely related strains e researchers created African Patient Patient person X Y his patients, then the strains of HIV found in his patients should be more closely related to his strain and less closely related to the strains from other infected people. The results showed that some of the dentist's patients probably were infected by him and that some probably were not. Two patients, X and Y, who could have been exposed to HIV as a result of their lifestyles or habits, had HIV strains that were not closely related to the dentist's strain. However, five other patients-A, B, C, D, and E-were carrying strains of the virus very closely related to the strain in the dentist. Moreover, those people were not at risk of contracting HIV by other means. So the scientists concluded that, at least in the case of these five patients, the dentist had infected them with his strain of the virus. Local non- patient 1 Local non- patient 2 Local non- Local non- patient 3 patient 4 Y K nary tree of the viral d in the dentist, in each ed patients, and in local An Evolutionary Tree Solves the Whodunit were also infected with Patient Patient Patient Dentist Patient Patient D