Introduction to Heredity and Disease

What you’ll learn to do: Explain the conventions of a family pedigree and predict whether a disease will be passed through a family in one of three modes

Over the years, we’ve seen that some diseases are hereditary. In this outcome, we’ll learn just how some diseases can be passed through a family line.

Family pedigrees and diseases can also be used to solve “mysteries,” such as the case of the Tsar of Russia and the missing Princess Anastasia. In this case, haemophilia within European royalty figured prominently in identifying the bodies of the murdered Russian royals (but not Princess Anastasia).

A family tree charting haemophilia in the descendants of Queen Victoria. Queen Victoria had three children: Princess Alice of the UK, Prince Leopold Duke of Albany, and Princess Beatrice of the UK. Of Queen Victoria's children, only Prince Leopold had haemophilia. Princess Alice had three children: Princess Irene, Prince Friedrich, and Alexandra Feodorovna. Of Princess Alice's children, only Prince Friedrich had haemophilia. Princess Irene had two sons, Prince Waldemar and Prince Heinrich, both of whom had haemophilia. Alexandra had one son, Alexy Nikolaevich, who had haemophilia. Queen Victoria's son Prince Leopold had one daughter, Princess Alice, who did not have haemophilia. Princess Alice had one son, Prince Rupert, who had haemophilia. Queen Victoria's daughter Princess Beatrice had three children: Victoria Eugenie, who did not have haemophilia, and two sons, prince Leopold of Battenberg and Prince Maurice of Battenberg, who both had haemophilia. Beatrice's daughter Victoria Eugenie had two sons, Alfonso of Spain and Infante Gonzalo of Spain, both of whom haemophilia.