1. Tracing the Evolution of Hepatitis C Virus in the United States, Japan, and Egypt By Using the Molecular Clock 
Masashi Mizokami, Yasuhito Tanaka 
Clinical Gastroenterology and Hepatology 
Volume 3, Pages S82-S85 (October 2005)
DOI: /S (05)
Copyright © 2005 American Gastroenterological Association Terms and Conditions

2. Figure 1
A phylogenetic tree within the NS5B region constructed by the neighbor-joining method. Closed circle indicates the most recent common ancestor of HCV-1a in the US, and open circle indicates the most recent common ancestor of HCV-1b in Japan.
Clinical Gastroenterology and Hepatology 2005 3, S82-S85DOI: ( /S (05) )
Copyright © 2005 American Gastroenterological Association Terms and Conditions

3. Figure 2
Estimating the most recent common ancestor of HCV-1a in the US on the basis of data collected during the last 3 decades. A regression analysis within the NS5B region was performed to estimate a mean molecular clock. The regression analysis with serial samples of US HCV-1a indicated the mean evolutionary rates of synonymous substitutions (P-B-L Model) (1.1 × 10−3 per site per year, P < .05). We estimated the time associated with zero branch length, ie, the time of the ancestral sequence, by using the above mean molecular clock by regression analysis. The divergence time of the most recent common ancestor of US HCV-1a was estimated to have occurred around 1910.
Clinical Gastroenterology and Hepatology 2005 3, S82-S85DOI: ( /S (05) )
Copyright © 2005 American Gastroenterological Association Terms and Conditions

4. Figure 3
Relative effective numbers of HCV infections among US, Japan, and Egypt. A rapid exponential growth of HCV-1b occurred in the 1920s among patients with schistosomiasis (Sj) in Japan, followed by HCV-1b of non-Sj group in Japan and HCV-4a in Egypt. The spread time of the US HCV-1a population was estimated to have occurred around 1960, more than 30 years later than the spread time of the HCV-1b population in Japan.
Clinical Gastroenterology and Hepatology 2005 3, S82-S85DOI: ( /S (05) )
Copyright © 2005 American Gastroenterological Association Terms and Conditions