![the symbol for female pedigree is x the symbol for female pedigree is x](https://vt-vtwa-assets.varsitytutors.com/vt-vtwa/uploads/problem_question_image/image/1457/pedigree.jpg)
A person who has no symptoms of the disease but has one normal and one abnormal gene is called a carrier. If one gene in the pair is abnormal, the disease does not occur, or at the very least, it is mild.
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Recessive inheritance is when both matching genes are abnormal for the particular trait and hence the disease is expressed. Those with the normal allele (B) do not show the condition.Ī) What is the genotype of both the mother and father of the first generation?ī) What is the genotype of an individual with the condition?Ĭ) What is the genotype of an individual who is a carrier?Į) Which word best describes an individual with the condition?ġ0) Sex-linked diseases are passed down through families through one of the sex chromosomes (X or Y). Solutionī) Is it possible that this pedigree can be for an autosomal dominant trait as well? SolutionĪ) Is it possible that this pedigree is for an autosomal recessive trait?ī) If so, what are possible genotypes of the father in the first generation?Ĭ) Give the possible genotypes of all the individuals.ĭ) Which two terms best describe the offspring of the first generation?Ĩ) If a trait is autosomal recessive, what can you conclude about the children of two parents that are affected?ĩ) The pedigree, on the right, shows the inheritance of a recessive disease caused by the allele ( b). The normal gene is given the symbol (A) while the recessive gene is given the symbol (a).Ī) Write the genotype of each individual. Horizontal lines connecting male and female indicate mating, while vertical lines connect parents to offspring.Ĭonsider the pedigree shown on the right it shows the inheritance of a specific trait.Ħ) The pedigree on the right shows a recessive genetic disease. Pedigrees make it easier to visualise inheritance of dominant or recessive genetic traits. Pedigrees use symbols, such as circles for females and squares for males to represent people and lines to represent family relationships. Family relationships can be represented in diagrammatic form.