Question

Traits that are determined by the action of more than one gene are a. recessive. b. not common. c. common in some organisms, but not in people. d. polygenic.

Short answer

d. polygenic

Step-by-step solution

Identify Key Terms

Understand what is meant by 'Traits determined by more than one gene.' This is crucial to narrow down the correct option.

Review Each Option

Analyze each answer choice: - **a. Recessive:** Traits are controlled by recessive and dominant alleles, but 'traits determined by more than one gene' doesn't relate directly to this.- **b. Not common:** This is vague and not specific to genetics.- **c. Common in some organisms, but not in people:** Traits determined by multiple genes are common in all organisms, including humans.- **d. Polygenic:** This term specifically means traits influenced by multiple genes.

Choose the Best Answer

Given the options and the understanding of polygenic traits, the best match for 'Traits that are determined by the action of more than one gene' is d. polygenic.

Key concepts

Genetics

Genetics is the study of heredity and the variation of inherited characteristics. It's a foundational concept in biology that explores how traits are passed from parents to offspring.
Genes, the units of heredity, are segments of DNA that determine specific traits. For instance, they can control eye color, hair color, and height.
Understanding genetics involves studying:**

• DNA structure and function
• Gene expression
• Mutation and variations

Genes can come in different forms, known as alleles. Each individual usually has two alleles for each gene, one from each parent. This combination determines the physical characteristics you see.

Multiple Genes

When a trait is influenced by multiple genes, it is known as a polygenic trait. Unlike simple traits controlled by a single gene (like Mendel's peas), polygenic traits involve the interaction of several genes.
These traits often display a continuous range of phenotypes rather than discrete categories.
Examples include:

• Height
• Skin color
• Weight

Because multiple genes contribute to these traits, there can be a wide variety of possible outcomes in the offspring.
Understanding polygenic traits is key in fields like genetics, biology, and evolutionary studies.

Inheritance Patterns

Inheritance patterns describe how traits are transmitted from parents to offspring. There are various patterns of inheritance, and the complexity increases with polygenic traits.
Here are a few patterns to know:

• Simple Mendelian: Traits controlled by a single gene with dominant and recessive alleles.
• Polygenic: Traits influenced by multiple genes, showing a range of phenotypes.
• Codominance: Both alleles express equally in the phenotype.
• Incomplete Dominance: The heterozygote has an intermediate phenotype.

Polygenic inheritance doesn't follow simple Mendelian rules. Instead, the combined effect of several genes results in a gradient of traits. For example, human skin color involves multiple genes, resulting in a spectrum of shades.
Understanding these inheritance patterns helps in predicting how traits are passed down and how genetic diseases might manifest.