2.4 Treacher Collins syndrome is characterised by deformed…
2.4 Treacher Collins syndrome is characterised by deformed or missing bones in the face. It is thought to be transmitted by the dominant allele T. Sever forms of the syndrome can result in life-threatening breathing difficulties. A Man with mild symptoms of Treacher Collins syndrome is heterozygous for the gene. His wife does not have the syndrome. Before deciding whether to have children, the couple wishes to know what the probability is of their child inheriting the condition. Complete the Punnet square to show the genotypes and the gametes of the couple, and the possible genotypes and the phenotypes of their children. Use T and t to represent the alleles. (3)