The science of cytogenetics is founded on the number of chromosomes and their structures.
Cytogenetics is the study of the relationship between chromosomal alterations and a genetic condition.
Down syndrome, for example, is a disability caused by the existence of an extra copy of chromosome 21 in the affected person.
This discipline of genetics helps us understand problems that are either genetically inherited or caused by chromosome abnormalities.
A girl kid born with only one X chromosome has Turner syndrome, and a male child with an extra X chromosome has Klinefelter syndrome, resulting in a total of 47 chromosomes.