Understanding Gamete Production from a Genotype

The question asks us to determine the number of different kinds of gametes that a plant with the genotype AABbCC will produce. Understanding how genes are inherited requires knowing how gametes are formed during meiosis.

A gamete is a haploid cell (like sperm or egg/pollen and ovule in plants) that contains only one allele for each gene. During meiosis, alleles for different genes assort independently (if they are on different chromosomes or far apart on the same chromosome), leading to different combinations of alleles in the resulting gametes.

Analyzing the Given Genotype AABbCC

The given genotype is AABbCC. Let's break down the gene pairs (loci):

• Gene A: The genotype is AA. This means the plant has two identical alleles for gene A (both are 'A'). This locus is homozygous.
• Gene B: The genotype is Bb. This means the plant has two different alleles for gene B (one 'B' and one 'b'). This locus is heterozygous.
• Gene C: The genotype is CC. This means the plant has two identical alleles for gene C (both are 'C'). This locus is homozygous.

Formula for Calculating Different Gametes

The number of different types of gametes that can be produced by an organism is determined by the number of heterozygous loci (gene pairs where the two alleles are different). The formula is:

Number of different gametes $= 2^n$

where $n$ is the number of heterozygous loci.

Applying the Formula to Genotype AABbCC

In the genotype AABbCC:

• The locus AA is homozygous.
• The locus Bb is heterozygous (here $n=1$ for this locus).
• The locus CC is homozygous.

Only the 'Bb' locus is heterozygous. Therefore, the number of heterozygous loci ($n$) is 1.

Using the formula, the number of different gametes is:

$2^n = 2^1 = 2$

Identifying the Different Gametes

Let's determine the specific types of gametes produced:

• From the AA locus, only allele 'A' can be passed to a gamete.
• From the Bb locus, either allele 'B' or allele 'b' can be passed to a gamete.
• From the CC locus, only allele 'C' can be passed to a gamete.

Combining these possibilities, the two different types of gametes are:

1. A (from AA) + B (from Bb) + C (from CC) → ABC
2. A (from AA) + b (from Bb) + C (from CC) → AbC

So, the plant with genotype AABbCC produces two different kinds of gametes: ABC and AbC.

Conclusion

Based on the analysis of the heterozygous loci in the genotype AABbCC and applying the $2^n$ formula, a plant with this genotype will produce 2 different types of gametes.