Wednesday, 13 February 2019

Tyger tyger

In 1977, I knew as much about inbreeding in captive tigers Panthera tigris as anyone on the planet. That was because I got access to data and the tools to analyse it and presented the results in a reasonably coherent report. The data was all the Dam-Sire-Cub triplets from Dublin Zoo since they started one of the early and very successful captive breeding projects. The tools were TCD's mainframe computer and some software written by a graduate student in Agricultural Genetics called Garry Mahon. Garry's programme, which was designed for horses and pedigree cattle, could work on any data where each individual had a unique ID and its parents were recorded. It generated a family tree and flagged cases where the same ancestor appeared in more than one branch. With a complete dataset it was a doddle to run several potential matings through the mill and decide which was least likely to  have offspring with a pair of deleterious [bad] recessive genes. I keyed all the data onto punched cards in the required format and Garry (who had much higher status than me) took the stack of cards to the computer centre and loaded them in to be number-crunched.
I was on a roll. In the Genetics Department library I found a copy of The Evolution of Man and Society by C.D Darlington; and in that book was a family tree of the Habsburgs. I keyed in that data as well and wrote a report showing that the inbreeding coefficient was inversely correlated with the number of legitimate offspring each Habsburg had. Golly-me, there were several instances where a papal dispensation was obtained to allow uncles to marry their nieces. Vice is nice; but incest is best - the game the whole family can play. These dynastic marriages were all about consolidating wealth and power even if the family developed. The last Uncle-Niece liaison produced Carlos II of Spain [extreme L in the group portrait above; with the extreme underbite which ran through the family] who was slow, short, lame, epileptic, senile "so ugly as to cause fear" and unable to produce an heir. That was possibly because his post-mortem revealed only a single shrivelled testicle. All that extra work at the interface between Arts & Science cut no ice with the examiners when I booted my final exams.

Having made some progress in zoological book-learning in college, I worked in a zoo (Diergaarde Blijdorp, NL) for about half a year in the late 1970s. I was happy-out working there and I finished with enough money to start Graduate School. Everyone was very good to me, even allowing me to choose which male was was to be sperm-donor for a gravid tropical reef-fish.  The problems of inbreeding are still relevant in the captive tiger community and zoos will ship likely males across Europe and across the world to minimise it. Last week one of London Zoo's tiger assets, a female called Melali, was matched with a young male from Denmark called Asim. Shortly after the prospective couple were introduced, Asim threw a strop and attacked Melali who subsequently died of her injuries. That's the downside of these arranged marriages, some unfortunate female is chosen for her dowry, fertility or connexions and she has to bed a ravin' nutter, a senile old drooler or Tio Felipe.

No comments:

Post a Comment