There is a relationship between chromosome gains, losses, or alterations to chromosome structure and a number of human diseases and genetic conditions.  An easily recognizable condition is Down Syndrome, a phenotype caused by the presence of an extra chromosome 21 (Trisomy 21).
Clinical cytogenetics includes evaluation of newborns and children with birth defects, study of individuals experiencing repeated or pregnancy loss or unexplained infertility, evaluation of prenatal and pre-implantation samples for chromosomal changes, and detection of cancer-associated chromosomal changes in patients with solid tumors and hematologic neoplasms.

Cytogenetic techniques include cell culture, chromosome preparation, G-banding, fluorescence in situ hybridization (FISH), comparative genomic hybridization, spectral karyotyping, and chromosomal microarrays.
The same techniques are used in cytogenetic research for studies on chromosome evolution, speciation, and genome stability…from mice and men, to monkeys and marsupials…from here at UCONN, to the San Diego Zoo, and Down Under, chromosome biology is an exciting area of inquiry in many academic and research facilities across the world.