Question

2 The inheritance of autosomal dominant traits also can be explored through pedigree analysis, Polydactylism, having extra digits, results from a dominant gene (P). Using Figure 3.8, explain the appearance of polydactyly in children of generation 3. O IIION FUR 8.8 Polydactylism pedigree. X-linked traits are carried exclusively on the X chromosome. Because a male possesses only one X chromosome, if he receives an X chromosome that carries an X-linked trat he will express that trait. For a female to express an X-linked trait, she will have to inherit two copies of the cene, ne on each x chromosome. Several conditions, such as hemophilia A and red-green color blindness, are X-linked recessive traits. 3 Using the following information, construct a pedigree for color blindness in three generations of a family in the sketch box provided, and answer the questions. In the first generation, neither parent was color blind. The second generation had four children. In their birth order. one was a normal female, one was a male that expressed the trait, another was a female that carried the trait but it was not expressed, and one was a normal male. a. The first born daughter, who was normal, had one normal daughter and one son who expressed the trait. How did this happen, and what is the genotype of the husband/father in this family? b. The second har male, who expressed the trait, had a son and daughter both of whom expressed the trait. How did this occur? 164 Exploring Biology in the Laboratory: Core Concepts

Answer 1

Staring with the first cross. The affected male can be PP or Pp. However, the progeny between this cross, results in a non affected child (pp). So, the affected father must be Pp Ppx pp P This second cross is the same as the first cross TOO Pp Pp Pp Pppp pp Pppp pp pp Рpx pp w 00 Рp Pp pp Рp pp Pppp Pppp p So, the generation 3 is basically result of a parents with a heterozygous genotype (Pp) and a homozygous recessive (pp) Note: According to Chegg's guidelines, you have to send just one question. Please, send each question separate so all experts can answer each of your questions. Thank you!.