Studying Chromosomes In 2017
Examining the structure of chromosomes
The first studies in human genetics were done in the early 1900s, well before we had any idea of the structure of DNA or chromosomes. It was not until the late 1950s that the double helix was deciphered, that we realised that chromosomes were large bundles of DNA, and that we were able to visualise the number and shape of chromosomes under the microscope.
In just a few years, numerous clinical disorders were identified as being due to abnormalities in the number or shape of chromosomes, and the field of “cytogenetics” was born.
Over the next five decades, techniques improved.
With the right sample and a good microscope, the laboratory could detect an abnormal gain or loss that was as small as 5-10 million base pairs of DNA on a specific chromosome. The light microscope reigned supreme as the ultimate tool for genetic analysis!
Examining the mass of chromosomes
In the last 10-15 years, a different technology called “microarrays” has ...