How to calculate probability of Phenylketonuria

In genetics, theoretical probability can be used to calculate the likelihood that offspring will be a certain sex, or that offspring will inherit a certain trait or disease if all outcomes are equally possible. It can also be used to calculate probabilities of traits in larger populations. Probability is a method for determining the likelihood of something uncertain occurring. If you flip a coin, you do not know whether it will be heads or tails, but probability can tell you that there is a 1/2 chance of either happening. If a doctor wants to calculate the probability that a couple’s future offspring will inherit a disease found on a specific genetic locus such as cystic fibrosis, she can also use probabilities. Consequently, professionals in the medical fields make great use of probabilities as do those in agriculture. Probability helps them with breeding of livestock, with weather predictions for farming and with crop yield predictions for the market. Problem: Phenylketonuria (PKU) is a human hereditary disease resulting from the inability of the body to process the chemical phenylalanine, which is contained in the protein that we eat. About 5 people per 1000 are carriers of PKU. Sara and James have never heard of PKU and were shocked to discover that their first child “John” had PKU. Sara’s identical twin sister Mary and her husband Frank are planning to have a child. Pedigree of Frank’s family has no known case of PKU. 1) What are the genotypes of Sara and James, Mary and Frank, respectively? 2) What is the probability that the second child of Sara and James will have PKU? 3) What is the probability that the first child of Mary and Frank will have PKU? 4) Sara and James are worried that their grandchildren from John will have PKU. What is the risk that one of their grandchildren (from John) will have PKU? #simpleProbability #math #Statistics #chances #coinToss #probabilityLine #likelyEvent #unlikelyEvent #NikolaysGeneticsLessons #geetics #pedigree #Genotype #Phenotype #probability #multiplicationRule #additionRule #mutuallyExclusive #IndependentEvents #crashCourse #crashcourse #stats #apStats #apStatistics #conditional #theoretical #empirical #independent #Education #introduction #sampleSpace #treeDiagrams #chance #Lesson #maths #data #probabilityFormula #basicProbability #biology