Let’s suppose a pea plant is heterozygous for three genes, Tt Yy Rr, and each gene is on a different chromosome. How many different wayscould the three pairs of homologous chromosomes line up during metaphase of meiosis I?

Figure 13.6 Which of the following statements about nondisjunction is true? Nondisjunction only results in gametes with n+1 or n-1 chromosomes. Nondisjunction occurring during meiosis II results in 50 percent normal gametes. Nondisjunction during meiosis I results in 50 percent normal gametes. Nondisjunction always results in four different kinds of gametes.

The chromosome constitution number of this individual is 2=6. This drawing represents: a. mitotic metaphase. b. meiotic metaphase I. c. meiotic metaphase II. d. a gamete. e. sixnonhomologous chromosomes.

Meiosis Explains Mendels Results: Genes Are on Chromosomes The following diagram shows a hypothetical diploid cell. The recessive allele for albinism is represented by a, and d represents the recessive allele for deafness. The normal alleles for these conditions are represented by A and D, respectively. a. According to the principle of segregation, what is segregating in this cell? b. According to Mendels principle of independent assortment, what is independently assorting in this cell? c. How many chromatids are in this cell? d. Write the genotype of the individual from whom this cell was taken. e. What is the phenotype of this individual? f. What stage of cell division is represented by this cell (prophase, metaphase, anaphase, or telophase of meiosis I, meiosis II, or mitosis)? g. After meiosis is complete, how many chromatids and chromosomes will be present in one of the four progeny cells?