What is represented by a karyotype?

A karyotype is a visual representation that displays all of a cell's chromosomes arranged in pairs, representing an individual's complete set of chromosomes. This arrangement is typically organized by size, shape, and number, allowing for the identification of chromosomal abnormalities such as aneuploidy or structural changes. By examining a karyotype, geneticists can determine the total number of chromosomes present and assess their characteristics, which is essential for diagnosing genetic disorders and understanding chromosomal contributions to health and disease.

The other options do not accurately describe what a karyotype conveys. A map of an individual's DNA would refer to a more detailed genetic sequence rather than a visual chromosome arrangement. A summary of gene expression pertains to which genes are actively being transcribed and translated in a cell, which is distinct from the structural organization of chromosomes. An analysis of a single chromosome would focus on the features of that specific chromosome rather than providing the complete picture of all chromosomes present in the cell.