Which of the following is heterozygous?
In genetics, the term “heterozygous” refers to a condition where an organism has two different alleles for a particular gene. This concept is fundamental to understanding the inheritance patterns of traits and the genetic diversity within populations. To clarify, let’s explore some examples and determine which of them is heterozygous.
The concept of heterozygosity is essential in genetics, as it helps us understand how traits are passed down from parents to offspring. In a heterozygous individual, one allele may be dominant, while the other is recessive. This scenario can lead to various genetic combinations and expressions of traits. Now, let’s delve into some examples to identify the heterozygous one.
Example 1: A plant with purple flowers and purple leaves.
In this case, the plant exhibits purple flowers and purple leaves, indicating that the dominant allele for flower color and leaf color is purple. However, to determine if the plant is heterozygous, we need to know the genetic makeup of its parents. If the parents were both purple-flowered and purple-leaved plants, they could be either homozygous dominant (PP) or heterozygous (Pp). If the plant in question inherited one purple allele from each parent, it would be heterozygous (Pp).
Example 2: A human with brown eyes and blue eyes.
Humans have two copies of each gene, one inherited from each parent. In this example, the individual has brown eyes, which is a dominant trait. However, the presence of blue eyes suggests that the individual has inherited a recessive allele for eye color. If the parents were both carriers of the blue eye allele, the individual would be heterozygous for eye color, with one dominant brown allele (B) and one recessive blue allele (b).
Example 3: A mouse with a long tail and a short tail.
In this example, the mouse has a long tail, which is a dominant trait. However, the presence of a short tail suggests that the mouse has inherited a recessive allele for tail length. If the parents were both long-tailed mice, they could be either homozygous dominant (LL) or heterozygous (Ll). If the mouse in question inherited one long-tail allele from each parent, it would be heterozygous (Ll).
After analyzing the examples, we can conclude that the heterozygous individual is the one with brown eyes and blue eyes (Example 2). This individual inherited one dominant brown allele (B) and one recessive blue allele (b), making it heterozygous for eye color. Understanding heterozygosity is crucial in genetics, as it helps us predict the inheritance patterns of traits and study genetic diversity within populations.
