Question

You are reading a scientific paper and come across the notation 12 q 24.1 when referring to the location of a gene for phenylketonuria. Describe the meaning of each of the numbers & letters in the notation.

Answer 1

The answer of the provided question is-

While reading a scientific paper, someone can come across the notation 12 q 24.1 when referring to the location of a gene for phenylketonuria. In the notation the number "12" indicates that a gene that is responsible (due to mutation) for causing the disease phenylketonuria is located on the chromosome no 12 .The letter "q" in the notation means that the gene for phenylketonuria is located on the "q" arm (i.e. the long arm) of the chromosome no 12. The number "2" of "24" in the notation means that the gene for phenylketonuria is located on the band (a region of chromosomal arm that can be observed by using special kind of stains and microscope) "2" of the "q" arm of chromosome no "12".The number "4" of "24" in the notation means that the gene for phenylketonuria is located on the sub-band (further division within a band or a region on a chromosomal arm) "4" of the band "2" of the "q" arm of chromosome no "12".The number "1" that is mentioned in the notation means that the gene responsible for phenylketonuria is located on the sub-sub-band (a further division within a sub-band of a band or a region on a chromosomal arm) "1" of the sub band "4" of band "2" of the "q" arm of chromosome no "12".

So, The notation 12 q 24.1 (referring the location of a gene for phenylketonuria) means that, the location of a gene responsible for causing the disease phenylketonuria is as follows-  

The gene is located on the chromosome no 12

The gene is located on the long arm i.e. "q" arm of the chromosome no 12

On the "q" arm of 12th  chromosome, the gene is located on the band 2

Within the band "2" of the "q" arm of 12th chromosome ,the gene is located on the sub-band 4

And within the sub-band 4 (that is located within the band "2" of the "q" arm of 12th chromosome), the gene is located on the sub-sub-band 1.