There's a slight misunderstanding in the question. It's not an allele that produces a heterozygous condition, but rather a combination of two different alleles that results in a heterozygous condition.

Here's a breakdown:

* Allele: An allele is a variant form of a gene. For example, a gene for eye color might have alleles for brown eyes, blue eyes, or green eyes.

* Heterozygous: A heterozygous individual has two different alleles for a particular gene. For example, someone with one brown eye allele and one blue eye allele would be heterozygous for eye color.

So, to be heterozygous, you need two different alleles, not just one.

Let me know if you have any more questions!