Imagine that a couple is planning to have children. The male is heterozygous for Huntington’s disease and homozygous dominant for Tay-Sachs. The female is homozygous recessive for Huntington’s disease and heterozygous for Tay-Sachs. The couple is curious about the possibility and probability of their offspring inheriting Tay-Sachs and/or Huntington’s. For humans, Huntington’s disease is dominant (H) over the “normal” condition (h), and the “normal” condition is dominant (T) over Tay-Sachs (t). Complete a Punnett square for this cross and record the probabilities for genotypes and phenotypes of the offspring as ratios.

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A: 50 percent chances.

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A: For this we will use binomial expression  P = n!/ x! (n-x!) * pxq(n-x)

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A:

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Inheritance and Mendelian Genetics

Inheritance means the passing of traits to offspring from parents. These traits could be passed either through asexual reproduction or sexual reproduction. The offspring receives the genetic material from the parents. Mendelian inheritance is a certain biological inheritance that follows the rules and principles laid down by Gregor Mendel in 1865. The initial hypothesis was considered wrong, but other inheritance theories modified the concept of inheritance and thus genetics.