Genotype as the Combination of Alleles Inherited by an Organism
Definition
Genotype
Genotype refers to the genetic makeup of an organism, specifically the combination of alleles it inherits for a particular trait.
- Understanding genetics starts with recognizing that genes are the basic units of heredity, but they come in different versions.
- These variations are what create diversity in traits.
Definition
Gene
A gene is a segment of DNA that codes for a specific trait, such as eye color or blood type.
Definition
Allele
An allele is a variation of a gene.
The gene for flower color in pea plants might have alleles for purple or white flowers.
Understanding Homozygous and Heterozygous Genotypes
- Homozygous genotype: When an organism inherits two identical alleles for a gene, it is homozygous.
- Heterozygous genotype: When an organism inherits two different alleles for a gene, it is heterozygous.
- BB (homozygous dominant) or bb (homozygous recessive) for tall/short plants.
- Bb (heterozygous tall) results in a tall plant because the dominant B allele masks the recessive b allele.
- Homozygous: Both alleles are the same (e.g., TT or tt)
- Heterozygous: Alleles are different (e.g., Tt).
- What is the difference between a gene and an allele? Provide an example to illustrate your answer.
- Explain the difference between homozygous and heterozygous genotypes. Why does a heterozygous genotype (Bb) result in a tall plant?
