Representative image. Photo: StartupStockPhotos/Pixabay
Many years of experience interviewing biology master’s graduates seeking admission to PhD programmes in the Centre for Cellular and Molecular Biology (CCMB) and the Centre for DNA Fingerprinting and Diagnostics (CDFD) tells me that a majority of them know that the DNA sequences of humans and chimpanzees are more than 95% similar.
A smaller fraction knows that our genome is distributed among 23 chromosomes (excluding the human Y chromosome), while the chimp’s is distributed among 24 chromosomes (again, excluding the chimp Y). A chromosome, whether of a human or chimp, has a single DNA molecule coursing through it from end to end. And almost none knew how to reconcile the DNA sequence similarity with the chromosome number difference.
A master’s graduate in biology ought to know that chimps and humans share very similar DNA. Knowing that they have different chromosome numbers is desirable, but not essential. And the challenge to reconcile these two seemingly disparate facts was thrown in to observe how well the candidate grappled with themselves to create a coherent explanation. [Explanation: In the time since we last shared a common ancestor with chimps, two chromosomes fused in the line that led to us, to make a single bigger chromosome. Someone trained in classical cytogenetics would make this connection.]
More worryingly, a large fraction could not answer the non-biology question, “If a pair of dice is rolled, what sum of the two numbers are you most likely to get?” Surely, many interviewees grew up playing board games with dice such as Snakes and Ladders or Ludo. Many simply blurt out, “Any number from one to twelve!”, then hasten to correct themselves: “…two to twelve”.
Sadly, both answers are wrong. The correct answer is seven. Readers need to only recall permutation and combination lessons from middle school to see why seven is more frequent than six and eight, and why two and twelve are the least frequent. The ability to reason things out is lost under stress. The stress is the interview itself. These are the most consequential 30 minutes in the candidate’s career.
Although anecdotal evidence suggests that more boys fly kites than girls, I could not tell whether more boys than girls could answer why one has to tug on the kite string to gain altitude. [Answer: The tug increases the distal surface’s curvature, increases the distance the wind has to travel, and hence wind speed over it. This lowers the air pressure relative to the proximal surface, and the pressure difference provides lift.] Maybe the fun of kite flying distracted the boys from appreciating the underlying physics.
A collective assessment of the candidate’s response to these and other questions and comparison with other candidates decided who got selected. The outcome was determined by what the panel thinks is an appropriate standard for any successful candidate to meet. And standards change over time.
Recently the geneticist and Brandeis University professor, James Haber, wrote that discoveries that were “had-to-teach” 25 years ago were now overwhelmed by newer discoveries. And since “there was no longer time to delve into these foundational papers. Out they went.” Discoveries in classical cytogenetics tend to be jettisoned from newer course material. This can explain why none of our interviewees thought of chromosome fusion.
The Junior Research Fellowship (JRF) selection interview is also significant for the faculty member under whom the selected candidates will do research for their PhD. Interviewees would do well to browse through the institute’s website to read about a few faculty research areas, and give thought to one or two which might also interest them. This would reduce their risk of being caught like deer in headlights.
Understandably, a faculty member would want to know a candidate’s interview performance before agreeing to take on the thesis supervisor’s role. But not all have the skill set to be effective interviewers. A poorly thought out question puts everybody off stride, wastes precious minutes, and in general undermines the process. On the other hand, new faculty members can acquire interviewing skills only from experience. Young faculty members are more abreast of newer trends in research. And it is good for the panel to have as much diversity as possible. Some interviewees might be more comfortable in a language other than English. One has to simply trust that the panel’s collective wisdom will correct for individual differences in empathy, experience, competence, and idiosyncrasy.
No selection process is perfect. Sometimes, deserving candidates are mistakenly failed, and unsuitable candidates mistakenly selected. Notwithstanding this, having an interview is better than not having one. It adds one more level of transparency and due diligence. Ultimately, the panellists have a personal stake in selecting the best candidates. Their career depends on it.
D.P. Kasbekar is a retired scientist.