Table 1 KEGG pathways increasing in abundance along a permafrost Pleistocene chronosequence.

From: Microbial survival strategies in ancient permafrost: insights from metagenomics

Pathway

19 vs 33 kyr

19 vs 27 kyr

27 vs 33 kyr

Two-component system

***

**

***

Valine, leucine and isoleucine degradation

***

**

*

Bacterial secretion system

***

***

***

ABC transporters

***

NS

***

Glyoxylate and dicarboxylate metabolism

***

***

***

Bacterial chemotaxis

***

NS

***

Lipopolysaccharide biosynthesis

***

NS

***

Phosphotransferase system

***

***

NS

Toluene degradation

***

NS

***

Cysteine and methionine metabolism

***

**

NS

Butanoate metabolism

**

***

NS

Peptiodglycan biosynthesis

**

NS

***

Fatty acid biosynthesis

***

NS

NS

Glutathione metabolism

***

NS

NS

Xylene degradation

**

NS

NS

Dioxin degradation

*

NS

NS

Geraniol degradation

**

NS

NS

Galactose metabolism

*

NS

NS

  1. Abbreviations: ABC, ATP-binding cassette; KEGG, Kyoto Encyclopedia of Genes and Genomes; NS, not significant.
  2. ***P<0.005.
  3. **P=0.01–0.005.
  4. *P=0.05–0.01.
  5. Data indicate whether the pathway was significantly more abundant in the older of the two age categories.