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Question 3.2

Annotation is to label the genome or genome sequence (usually unknown organisms), i.e.

to understand its content and function. Reannotation is used to check an existing annota­

tion, for example in the case of new genes or sequencing techniques. It is best to read up

on this again in the book chapter.

Question 3.3

There are now a number of different sequencing techniques. You should be familiar with

the classical sequencing technique according to Sanger (chain termination synthesis) and

the more advanced methods, so-called next generation sequencing, such as pyrosequenc­

ing (Roche 454) and sequencing by synthesis (Illumina) (second generation) and nanopore

sequencing (third generation).

Question 3.4

Here you should know DNA labeling, sequencing (shotgun method), mapping, assembly

and annotation. Challenges are, among others, the computer performance, but also the

memory requirements, due to the flood of sequences, by sequencing techniques that are

getting better and faster. Furthermore, there are also problems, especially with repeat

regions, to represent them correctly in their length and number of repeats.

Important pioneers are Frederick Sanger (chain termination synthesis), Craig Venter

and Erik Lander (first “draft” sequence of the human genome in 2001).

Question 3.5

We had already mentioned a few points here in Task 3.4 (computer performance, memory

requirements). The secure handling and use of data (confidential treatment, avoidance of

data misuse, data protection) etc. are certainly also important.

Question 3.6

Here, for example, there are the online libraries NCBI and EBI, but also the genome

browsers UCSC and Ensembl.

Questions 3.7 and 3.8

The cell nucleus, also called the nucleus, contains the entire genetic material of an organ­

ism, i.e. the DNA. The DNA consists of genes that code for specific proteins, such as

enzymes, hormones or transcription factors, which fulfil important tasks in the organism.

In order to form a protein, i.e. the active form of a gene, the information of a gene must

first be read. This process is also known as gene expression, whereby a distinction is made

between the two processes of transcription (formation of mRNA on the basis of a DNA

sequence) and translation. The analysis of DNA sequences is important, for example to

20  Solutions to the Exercises