What is a karyotype?

A karyotype refers to the number and appearance of chromosomes in the nucleus of a eukaryotic cell. This includes not only the overall number of chromosomes but also their size, shape, and organization into homologous pairs. Karyotyping is a vital tool in genetics, often used to identify chromosomal abnormalities, such as aneuploidies, deletions, and translocations, which can lead to various genetic disorders.

For example, in a normal human karyotype, there are 46 chromosomes arranged in 23 pairs, with specific characteristics like the length of the p and q arms, the position of the centromeres, and the banding pattern that can be visualized during cell division. This detailed analysis helps geneticists determine potential health issues and understand an individual's genetic makeup comprehensively.

The other options do not accurately define what a karyotype entails. The sum of all genes in an organism describes the genome, whereas the total number of chromosomes in a cell provides a basic count without including the specific arrangement and structural information that karyotyping entails. An assessment of genetic mutations pertains to identifying changes in the DNA sequence rather than the overall structural analysis of chromosomes.