Joe Hin Tjio & Albert Levan, “The Chromosome Number of Man”, 1956 was the topic of an earlier blog post.
Here I present: Joe Tjio & Albert Levan, The Chromosome Number’ of Man, 1956, PART TWO (II).
INTRODUCTION.
Joe Hin Tjio 蔣有興 is renowned as the first person to recognize the normal number of human chromosomes on the 22 December 1955 at the Institute of Genetics of the University of Lund, Sweden. This 1956 paper with Albert Levan was the beginning of the nomenclature. The nomenclature went through five (5) modifications listed BELOW.
- Denver 1960
- London 1963
- Chicago 1966
- Paris 1971
- Baltimore 1985
Here I presented: Joe Hin Tjio and Albert Levan, The Chromosome Number’ of Man’, 1956, PART TWO (II).
COMMENTS.
1. The short-arm is “p” at the top; and, the long-arm is “q” the bottom.
2. Chromosomes reading from left to right adds more bands.
3. As you move left to right, you reach a point of no change.
4. The sequence is: Denver 1960, London 1963, Chicago 1966, Paris 1971, Baltimore 1985.
EXAMPLES.
I. Chromosome #Y has no new bands after Chicago 1966. At this time Yq11.3 became Yq11.31 & Yq11.32
II. Chromosome #22 has no new bands after Paris 1971. At this time 22q13.3 became 22q13.1 , 22q13.2 & 22q13.3
III. Chromosome #21 has no new bands after Paris 1971. At this time 21q22.1 became 21q22.11, 21q22.12 & 21q22.13
REMARK.
In 1956 when Joe Hin Tjio correctly counted the chromosomes, the only designations were groups A, B, C, D, E, F, G. 
