Mendelian genetics

So far this chapter has examined the biology of genetics, and now it is going to look at the role
of genetics in inheritance. This is very important because, as stated previously, what we are is
designated to a large extent by our genetic make-up – which is inherited from our parents. The
caveat ‘to a large extent’ is because as well as being a product of our genes we are also a product
of our environment – time, space, relationships, education, and so on.
So how do we inherit our genes from our parents? To understand this we have to return to the
1860s. In Brno (which is now a large town in the Czech Republic but was then a small, sleepy
town in Bohemia) there was a monastery, and in that monastery there lived and worked a monk
with a very inquiring mind. His name was Gregor Mendel and he worked in the monastery
gardens
where he put his mind to good use trying to perfect the ideal pea. As part of this work,
he experimented with cross‐breeding. Now, at that time, cross‐breeding went on everywhere –
on farms and in gardens; and of course, we humans cross‐breed as well. However, what was
different about Mendel was that not only did he experiment with cross‐breeding different peas,
but he also made notes on his experiments and observations. He introduced three novel
approaches to the study of cross‐breeding – at least novel for his time, because no one else was
doing this. Not only did he observe, but he experimented and observed. Having observed and
experimented he then used statistics. He ensured that the original parental stocks, from which
his crosses were derived, were pure breeding stocks (the use of statistics was not at that time
fully part of the tradition of biology).