Dynamics of Escherichia coli type I‐E CRISPR spacers over 42 000 years

• Published in: Molecular ecology Vol. 26; no. 7; pp. 2019 - 2026
• Main Authors: Savitskaya, Ekaterina, Lopatina, Anna, Medvedeva, Sofia, Kapustin, Mikhail, Shmakov, Sergey, Tikhonov, Alexey, Artamonova, Irena I., Logacheva, Maria, Severinov, Konstantin
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.04.2017
• Subjects: ancestry; Animals; bacteria; Biological Evolution; Clustered Regularly Interspaced Short Palindromic Repeats; CRISPR arrays; CRISPR spacers; DNA; DNA, Ancient; DNA, Bacterial - genetics; E coli; Escherichia coli; Escherichia coli - genetics; immune system; interspersed repetitive sequences; intestines; Intestines - microbiology; Mammoths - microbiology; Nucleic acids; palaeo DNA; Sequence Analysis, DNA; CRISPR arrays; CRISPR spacers; Escherichia coli; palaeo DNA
• ISSN: 0962-1083; 1365-294X; 1365-294X
• DOI: 10.1111/mec.13961

CRISPR‐Cas are nucleic acid‐based prokaryotic immune systems. CRISPR arrays accumulate spacers from foreign DNA and provide resistance to mobile genetic elements containing identical or similar sequences. Thus, the set of spacers present in a given bacterium can be regarded as a record of encounters of its ancestors with genetic invaders. Such records should be specific for different lineages and change with time, as earlier acquired spacers get obsolete and are lost. Here, we studied type I‐E CRISPR spacers of Escherichia coli from extinct pachyderm. We find that many spacers recovered from intestines of a 42 000‐year‐old mammoth match spacers of present‐day E. coli. Present‐day CRISPR arrays can be reconstructed from palaeo sequences, indicating that the order of spacers has also been preserved. The results suggest that E. coli CRISPR arrays were not subject to intensive change through adaptive acquisition during this time.