- Calvin Bridges was the golden boy, strikingly good looking, who pioneered the use of polytene chromosomes to help map genes. He died young of "died of heart failure due to complications from a heart valve infection" . . . ahem, read that as syphilis: he parlayed his good looks into a parallel career as a serial womaniser.
- AH Sturtevant was the steady one, who produced the first evidence that some gene variants were inherited together. With Bridges, he followed Morgan from Columbia to Cal Tech in 1928.
- Hermann Muller, was Cinderella to these two favored students. He was the ideas man who got serially hacked off when his contributions weren't acknowledged in publications. There was a hint of anti-semitism in his treatment by Morgan but we were encouraged to demonise Muller because a) he emigrated to Germany and then the USSR in the 1930s and b) was a advocate of eugenics.
She wasn't looking at the human karyotype: we didn't even get the correct number of our chromosomes until Tjio and Levan counted them in 1955! Stevens was concentrating her attention on Tenebrio molitor the common mealworm beetle. She noticed that female beetles had 20 large chromosomes while males had 19 and a speck. Doubtless she didn't believe her eyes or her counts until she'd done it again and again to be sure to be sure. It is very difficult now to appreciate how earth-shaking this ultimately correct idea was at the time. Sex-determination was treated as a philosophical, as much as a biological problem and despite her compelling evidence, Morgan and others clung to a role for external forces in the process for several subsequent years. Also reflect that Mendel's theory of particulate inheritance had only been [re-]discovered in 1901, 4 years before Stevens' seminal paper. Her microscope [L] is in a glass case in Bryn Mawr, partly to show how poorly designed it is ergonomically and how hard it was for Stevens to be comfortable while peering. Morgan went on to get the 1933 Nobel Prize in Physiology and Medicine for his work on chromosomes. He shared the cash with Bridges and Sturtevant. Even if he'd had a mind to, he couldn't have included Nettie Stevens in the bonanza because she was dead - 1912, breast cancer aged 50. She was late to the academic scene and did her best work in her 40s, having been born on this day, 7th May 1861, 155 year ago.