The sweet pea, Lathyrus odoratus, is a flowering plant that grows in many parts of Europe. The inheritance of flower colour and shape of pollen grains is controlled by genes that display autosomal linkage.

1. (a)Explain what is meant by autosomal linkage.[2]
2. (b)In sweet peas, the allele for purple flowers is dominant to the allele for red flowers and the allele for long pollen grains is dominant to the allele for round pollen grains. A sweet pea plant that is heterozygous for both purple flowers and long pollen grains is crossed with a sweet pea plant with red flowers and round pollen grains. The results of this cross are shown in Table 8.1. Table 8.1 offspring phenotype percentage of offspring purple flowers, long pollen grains 44 red flowers, round pollen grains 44 purple flowers, round pollen grains 6 red flowers, long pollen grains 6 Describe and explain the results shown in Table 8.1.[4]
3. (c)Different alleles affecting flower colour in the sweet pea plant are the result of gene mutations. State how a gene mutation may occur.[3]