Chapter 26

Medicine and Disease

The question that this chapter tries to answer is, “what use is bioinformatics for

medicine?” Medicine is primarily concerned with the cure of ill health, and the

maintenance of good health. ¹ The connexion between DNA and illness once seemed

clear. Some diseases have a clear genetic signature. Well-characterized diseases such

as sickle-cell anaemia, known to be caused by a single point mutation in the gene

coding for haemoglobin, seemed to provide solid confirmation of the “one gene,

one enzyme” hypothesis. Another example of a genetic disease: normal individuals

have about 30 repeats of the nucleotide triplet CGG, whereas patients suffering from

fragile X syndrome have hundreds or thousands.

On the other hand, many common diseases (e.g., asthma, diabetes and epilepsy)

appear to have a genetic basis but lack the simple patterns of inheritance that would

allow one to infer that they are the result of disorder in a single gene. Such polygenic

diseases are likely much more common than single-gene diseases. Furthermore,

their incidence is known to be increasing and, although this is often attributed to

environmental factors, it has been argued that it is a result of population mixing, ²

itself a corollary of globalization; the mixing tends to reintroduce susceptibility genes

exogenously, which endogenously had been selected against (it can be assumed that

the populations being mixed, having previously existed in different environments,

have different sets of susceptibilities and resistances). Note the contrast with the

benefits of mixing for diminishing the incidence of single-gene recessive diseases. ³

1 Some would also argue for a preventive role, but the primacy of the curative purpose is indisputable.

See Ramsden (2021) for more discussion.

2 Awdeh and Alper (2005), Awdeh et al. (2006).

3 The antithesis of polygenicity, pleiotropy (one gene affecting many traits), has been shown in at

least one case to stabilize coöperation (Foster et al. 2004)—cf. Sect. 4.1.1.

© Springer Nature Switzerland AG 2023

J. Ramsden, Bioinformatics, Computational Biology,

https://doi.org/10.1007/978-3-030-45607-8_26

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