Final answer:
A scientist involved in analyzing chromosomal composition for genetic research and diagnosis of chromosomal abnormalities is known as a geneticist. They use karyotyping, a method by which abnormalities can be identified from a single cell.
Step-by-step explanation:
A scientist who examines the chromosomal composition of a particular cell is called a geneticist. Geneticists are experts in the field of genetics, which is the study of heredity and the variation of inherited characteristics. They may use a cytological technique known as karyotyping, a method by which traits characterized by chromosomal abnormalities can be identified from a single cell. To observe an individual's karyotype, geneticists collect cells, such as white blood cells, from a blood sample or other tissue. In the lab, these cells are stimulated to divide, treated with colchicine to arrest condensed chromosomes during metaphase, and then induced to swell using a hypotonic solution to spread the chromosomes apart. After preserving the sample with a fixative, the geneticist stains chromosomes, views them under a microscope, and identifies banding patterns, size, and centromere location. This information is used to manually arrange the chromosomes into a classic depiction of the karyotype, where homologous pairs of chromosomes are aligned in numerical order.
Although cytotechnologists are professionals who study cells and notice abnormalities at a microscopic level, the specific role of analyzing chromosomes for genetic research and diagnosis of chromosomal abnormalities falls to geneticists who are specialized in cytogenetics, the study of chromosome structures and function.