Purification of Chromosomes from Plasmodium falciparum

Sequencing of the entire genome from the human malaria parasite, Plasmodium falciparum , began in earnest in 1996 with the formation of an international consortium of scientists and funding agencies (1 ). Due to the instability of the highly adenine (A) and thymine (T)-rich P. falciparum DNA in large insert bacterial vectors, and to distribute the enormous task of completing the 30 Mb genome among several genome centers, the decision was made to sequence the P. falciparum genome by chromosome. Obtaining pure chromosome material, free of contaminating DNA and in sufficient yield, is of paramount importance in order to produce sequencing libraries that are as unbiased and as representative of the genome as possible. Minimizing the amount of cross-contaminating chromosomal DNA is critical to reduce costs and ensure accurate assembly of the sequence. To date, the sequences of two chromosomes from P. falciparum have been published, chromosome 2 (2 ) and chromosome 3 (3 ), and it is anticipated that the remainder will be completed by the end of 2002.