#### In a genetic cross between two plants with the genotypes AaBbCcDd and AaBbCcDd, what is the probability of obtaining an offspring with the genotype AABBCCDD?Option: 1 $\frac{1}{256}$Option: 2 $\frac{1}{128}$Option: 3 $\frac{1}{64}$Option: 4 $\frac{1}{32}$

In this cross, both parents are heterozygous for four different genes. To determine the probability of obtaining an offspring with the genotype AABBCCDD, we need to consider the segregation of alleles for each gene and their combination in the offspring.

Since both parents are AaBbCcDd, each parent can produce gametes with four possible alleles: AB, Ab, aB and ab for the A and B genes, similarly for the C and D genes. Thus, each parent can produce $4 \times 4=16$different gamete combinations.

To obtain the genotype AABBCCDD in the offspring, we need to consider the probability of obtaining the corresponding alleles from each parent. Since each parent has one copy of allele, the probability of getting the desired allele for each gene is 1/2.

Therefore,the probability of obtaining the genotype AABBCCDD from both parents is  $\frac{1}{16} \times \frac{1}{16} \times \frac{1}{16} \times \frac{1}{16} = \frac{1}{256}$