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exponential growth of possibilities, e.g., the traveling salesman’s problem of driving to

numerous cities along the most optimal route possible. The same is true for the prediction

of protein structure (whether ab initio in three dimensions or as a homology model), the

calculation of stable system states for pathways (for example, in the cancer cell), and

metabolic modeling. Many exciting biological problems are NP problems. Typically, in an

NP problem, I don’t know exactly when I will find the solution, no matter what computer

algorithm I use. However, if I am shown the solution, I can confirm it in polynomial time

(i.e., rather quickly).

Omics  Branch of biology that deals with the analysis of large amounts of biological data.

Examples are proteomics, metabolomics, genomics, RNAomics, interactomics, which

deal with big data about proteins, metabolites, genomes, RNA and interactions.

Ordered Systems  Description of systems by simple mathematical equations, where the

behaviour is predictable and can be described exactly for the entire period of the flight or

train journey, e.g. flight of a rocket. 

Pandemic  An epidemic spreading worldwide (epidemic = contagious disease, infectious

disease). Currently (2020) a pandemic is caused by the virus Sars-CoV-2 (severe acute

respiratory syndrome coronavirus 2). This is a coronavirus (cause respiratory disease; they

have a ring, a “corona” of appendages around the spherical body). Pedigree analyses show

high relatedness to the SARS virus (2002/2003 pandemic). Another relative is the MERS-

CoV (Middle East respiratory syndrome coronavirus). A pandemic with many millions of

deaths was the “Spanish flu” after World War 1. Important for a pandemic are factors that

ensure a steady spread of the disease across many national borders and thus worldwide

(the factor R0, the infection rate per infected person always remains at least slightly above

1, so that there are always more people infected). This can be well modelled bioinformati­

cally, as can the effect of control measures, mutation rates, mortality, changes in the infec­

tion rate. 

Parsimony  Phylogenetic procedure in which the mostly not directly observable ances­

tors are calculated in such a way that all observed present-day sequences can be generated

with as few mutations of these ancestor sequences as possible.

Polymerase  enzyme that produces a new nucleic acid. This is usually done according to

a template. There are RNA-producing RNA polymerases and DNA-producing DNA

polymerases. 

Polymerase Chain Reaction (PCR)  Method of molecular biology that serves to double

the genetic information (DNA) by means of a chain reaction (constant doubling of the

DNA strands). In order to achieve this specifically for a certain DNA sequence, one needs

the start of the desired sequence and determines a complementary initial sequence (start

primer) and at the end of the sequence on the opposite strand a reverse primer that is again

complementary to it. With the help of the two primers, one specifies where a new strand is

to be synthesized for the polymerase that is also required. After about 1 min of DNA syn­

18  Glossary