For each of the following scenarios, explain how graph theory could be used to model the problem described and what a solution to the problem corresponds to in your graph model.

To determine the order in which the nucleotide bases (A,C,G,T) occur in a long string of DNA, such as in a chromosome, one common approach is to cut large DNA fragments into shorter DNA fragments. The short DNA fragments are individually sequenced and then these
short sequences are assembled into one long, contiguous sequence. This assembly process is complex and dicult, particularly if a sequence contains many repeats.

To illustrate how graph theory can model this problem, you might like to use the following small example. Suppose that a biologist has the following DNA fragment of length 13 but does not know the sequences of bases

ACGTCCGTCACGT:

Replication and cutting gives the biologist the following list of fragments of length three.

ACG CGT GTC TCC CCG TCA CAC

(b) A speed dating evening has been organised so that each member of a group of women can meet with each member of a group of men for a 10 minute conversation, to determine whether or not they might want to meet again. The event organiser has to give each person a schedule indicating which table to sit at during each time slot to ensure that each woman meets each man.

To illustrate how graph theory can model this problem, you might like to consider an evening where an equal number of women and men show up and also an evening where the numbers of women and men are unequal.