History of Karyotype Development 

The concept of the karyotype has a rich history that spans more than a century. In 1842, the German botanist Carl Wilhelm von Nägeli first observed thread-like structures in plant cells, which he referred to as transitory cytoplasts later recognized as chromosomes [Reference]. This was followed by Walther Flemming in 1882, who carefully described the behavior of chromosomes in animal cells, laying the groundwork for cytogenetics [Reference]. In 1888, the German anatomist Heinrich von Waldeyer introduced the term chromosome [Reference]. Later, term "karyotype" was introduced by the Russian botanist Grigorii Levitsky in 1931 [Reference]. By 1922, the definition of a karyotype was refined to mean the phenotypic appearance of somatic chromosomes, and during the early 20th century, as genetics advanced, it became clear that chromosomes were the carriers of genes. 

A major milestone came in 1956, when Joe Hin Tjio and Albert Levan used improved techniques to correctly determine the human chromosome number as 46, establishing the modern foundation of karyotype analysis [Reference]. 

Karyotype Definition

A karyotype is the complete set of chromosomes in an organism, arranged and displayed in a systematic order based on their size, shape, and number. It provides a visual profile of an individual's chromosomes, showing their structural characteristics and allowing the identification of chromosomal abnormalities.

Karyotype Groups:

In humans, the chromosomes are grouped into seven categories based on their size and the position of the centromere (the part of a chromosome that links sister chromatids). These groups are as follows: