Final answer:
The probability of children being deaf from parents carrying different autosomal recessive deafness alleles on separate chromosomes is effectively 0%, (option a) as the chance of both specific alleles being inherited is extremely low.
Step-by-step explanation:
Understanding Autosomal Recessive Inheritance and the Probability of Deafness in Offspring
A man with normal hearing who carries a recessive deafness allele on chromosome 17 and a woman with normal hearing who carries a recessive deafness allele on chromosome 3 are considering the likelihood that their children will be deaf. To determine this probability, we need to understand how autosomal recessive inheritance works. If both parents carry different autosomal recessive alleles for deafness, each on a different chromosome, the chance of both recessive alleles coming together in an offspring is quite low, as it would require a very specific combination of inheritance.
According to Mendelian genetics, when parents are carriers of an autosomal recessive disorder, such as cystic fibrosis, represented by the alleles 'Ff', there is a 25% probability the child will inherit the disorder (ff). However, this applies to a situation where both recessive alleles are for the same condition and on the same gene locus. In our case, since the recessive deafness alleles are on different chromosomes, each child will most likely inherit only one recessive allele from either parent, maintaining normal hearing but also becoming a carrier.
Therefore, for a child to be deaf due to these specific alleles, they would have to inherit the specific recessive deafness allele from the father located on chromosome 17 and the specific recessive deafness allele from the mother located on chromosome 3, an event which, without linkage of these genes, has an extremely low probability and does not align with any Mendelian inheritance ratio. Consequently, the probability of their children being deaf due to these mutated genes is closest to 0% (Option A).