Here's a breakdown:
* Gene: A segment of DNA that codes for a specific trait.
* Allele: Different versions of a gene.
* Heterozygous: Having two different alleles for a particular gene.
Example:
Let's say the gene for eye color has two alleles: one for brown eyes (B) and one for blue eyes (b).
* Homozygous dominant: BB (brown eyes)
* Homozygous recessive: bb (blue eyes)
* Heterozygous: Bb (brown eyes, because brown is dominant over blue)
Key Points:
* Dominant Allele: The allele that is expressed even when paired with a recessive allele.
* Recessive Allele: The allele that is only expressed when paired with another recessive allele.
* Phenotype: The physical expression of a trait (e.g., brown eyes).
* Genotype: The genetic makeup of an individual (e.g., Bb).
In summary, being heterozygous means carrying two different alleles for a gene, which can lead to different phenotypes depending on the dominance relationship between the alleles.
