Museum piece: PCR identifies 'Irish famine' pathogen

Curators of the world's natural history collections face a tough task obtaining the funds needed to preserve material that some critics regard as a waste of space. Perhaps the value of the collections will be appreciated more as new techniques applied to the old samples begin to yield information beyond the obvious taxonomic and curiosity value. Stomata counts of leaf samples from herbariums were recently used as a record of the past 200 years of climate history, tracking atmospheric CO₂ into the industrial age. And now the plant pathogen responsible for the nineteenth century Irish potato famine has been identified by sequencing DNA obtained by PCR from museum and herbarium samples of infected potatoes and tomatoes. Surprisingly, the Phytophthera infestans (late blight) found in nineteenth century specimens was not the expected ancestral clone, thought to have arisen in Mexico and ubiquitous throughout the past century, but a quite different strain originating in South America. The surprising result highlights the importance of using historic specimens when making inferences about historic populations.

PCR amplification of the Irish potato famine pathogen from historic specimens
JEAN B. RISTAINO, CAROL T. GROVES & GREGORY R. PARRA
Nature 411, 695-697 (7 June 2001)
| First Paragraph | Full Text | PDF (175 K) | Supplementary Information |

Plant pathology: Reverend Berkeley's devil
NICHOLAS P. MONEY
The potato famine of 1845-1846 had a devastating effect on Ireland. DNA analysis of herbarium specimens has allowed identification of the strain of plant pathogen responsible.
Nature 411, 644-645 (7 June 2001)
| Full Text | PDF (159 K) |

relics: Fungus forensics shift blame for blight

7 June 2001 table of contents