Final answer:
Jim's genotype is either Aa or aa, as he inherits the recessive allele 'a' from his father Tom, who is aa, and can inherit either 'A' or 'a' from his mother Sue, who is Aa. Without knowing Jim's phenotype, we cannot determine his exact genotype.
Step-by-step explanation:
The question pertains to a pedigree chart for an autosomal dominant trait. Given that Sue's genotype is Aa (heterozygous) and Tom's genotype is aa (homozygous recessive), we can predict the genotype of their son Jim. Using simple Mendelian inheritance, we know that Jim will inherit one allele from each parent. Since Tom can only pass the recessive allele 'a', and Sue has the possibility to pass either her dominant 'A' or recessive 'a' allele, Jim can either be Aa or aa.
In such a cross, there is a 50% chance for each genotype to be inherited by their offspring. Therefore, there are two possible genotypes for Jim: Aa - inheriting the dominant allele from Sue (meaning he would express the dominant trait), or aa - inheriting the recessive allele from Sue (meaning he would not express the dominant trait). However, without information on Jim's phenotype, we cannot precisely determine his genotype. Hence, without additional information, we cannot definitively say which genotype Jim has, but we can say he must have one recessive allele 'a' from his father.