Define the terms allele, chromosome, and gene, and explain how they relate to one another. Develop an analogy between these terms and the process of using a street map to locate a new apartment to live in next year (i.e., consider which term is analogous to a street, which to a type of building, and which to an apartment floor plan).

Key Concepts

Allele

An allele is a variant form of a gene that arises by mutation and is found at the same place on a chromosome. Alleles can be dominant or recessive, influencing the traits expressed in an organism. In the analogy, an allele can be compared to a specific street name on a map, representing a particular variation of a location.

Chromosome

A chromosome is a long, thread-like structure made of DNA and proteins that contains many genes. Humans typically have 23 pairs of chromosomes, which carry the genetic information necessary for development and functioning. In the analogy, a chromosome can be likened to the entire street grid on a map, encompassing various streets (alleles) and buildings (genes) within a defined area.

Gene

A gene is a segment of DNA that contains the instructions for building proteins, which determine the traits of an organism. Genes are the basic units of heredity and can exist in different forms (alleles). In the analogy, a gene can be compared to a specific building type on a street, representing a particular characteristic or function within the broader context of the chromosome (street grid).