A trait controlled by a gene at several loci is an example of

Options

A. Multiple allelism
B. Incomplete dominance
C. Pleiotropy
D. Polygenic inhertance

Answer

To solve the question "A trait controlled by a gene at several loci is an example of," we need to understand the concepts of genetic inheritance. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Terminology
- **Trait**: A characteristic or feature of an organism.
- **Gene**: A segment of DNA that codes for a specific trait.
- **Loci (plural of locus)**: The specific location of a gene on a chromosome.

### Step 2: Identify the Type of Inheritance
- The question mentions a trait controlled by a gene at several loci. This indicates that multiple genes are involved in determining a single trait.

### Step 3: Define Polygenic Inheritance
- **Polygenic Inheritance**: This is a type of inheritance where one trait is controlled by two or more genes. Each of these genes may have multiple alleles, and their combined effects contribute to the phenotype of the trait.

### Step 4: Examples of Polygenic Traits
- Common examples of polygenic traits include:
- **Height**: Influenced by many genes (approximately 700 genes).
- **Skin Color**: Also influenced by multiple genes (around 370 genes).

### Step 5: Review Other Options
- **Multiple Allelism**: Involves a single gene with more than two alleles (e.g., blood groups).
- **Incomplete Dominance**: A situation where the heterozygous phenotype is a blend of the two homozygous phenotypes (e.g., pink flowers from red and white parents).
- **Pleiotropy**: A single gene affecting multiple traits (e.g., one gene influencing both seed shape and starch synthesis in peas).

### Step 6: Conclusion
- Since the question specifically asks about a trait controlled by several loci (indicating multiple genes), the correct answer is **Polygenic Inheritance**.

### Final Answer
- The answer to the question is **Polygenic Inheritance**.

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