Final answer:
The number of different types of gametes possible in humans, without crossing-over, is 32. In the case of 23 chromosome pairs, this equals 2^23 combinations. A specific genotype like AaBb can produce 4 types of gametes: AB, Ab, aB, ab.
Step-by-step explanation:
In humans, the number of different types of gametes possible, assuming no crossing-over, is 32. This is because humans have 23 pairs of chromosomes and each gamete receives one chromosome from each pair. The number of possible combinations or types of gametes can be calculated using the formula 2^n where n is the number of chromosome pairs.
For example, in the case where a muscle cell of a typical organism has 32 chromosomes, a gamete of that organism would have half the number of chromosomes, which is 16 chromosomes, because gametes are haploid cells. If a gene has four different alleles circulating within a population, the number of possible genotypes can be calculated using the binomial theorem, considering the case where there could be homozygous and heterozygous combinations.