I looked at 3 groups of viruses:
"2004": 11 H5N1- viruses from Henan,2004
"1997": 6 H5N1 - viruses from Hubei,1997
"1977": 19 avian viruses from Hongkong, 1975-1979
the minimum distance between the groups in the 8 segements is:
(distance=1/100 % of nucleotides changed)
This is very low.
to compare: the average distance of a Qinghai-virus to the
original Qinghai-strain from Febr.2005 is 030 per year !
that would make 600 for 1977-1997, 210 for 1997-2004, 810 for 1977-2004
For 1968 H3N2 the rate was also about 030 for the first 5 years,
but then it went down to ~020. I assume in new reassorted viruses
the mutation rate is higher because more mutations survive
when the sequences are not yet very optimal.
human H3N2, 1968(1972)-1998:492,594,510,1284,543,828,363,534
There are also some examples for preserved sequences in swine.
I'm not aware of such examples of low mutation rates
in human influenza except the "freeze" 1957-1977 in H1N1,
lab-escapes or vaccine strains.
schina
"2004": 11 H5N1- viruses from Henan,2004
"1997": 6 H5N1 - viruses from Hubei,1997
"1977": 19 avian viruses from Hongkong, 1975-1979
the minimum distance between the groups in the 8 segements is:
Code:
1977-1997: 346,119,183,735,146,1069,097,123 1997-2004: 100,030,079,191,033,0143,038,089 1977-2004: 290,114,167,810,133,1080,136,191
This is very low.
to compare: the average distance of a Qinghai-virus to the
original Qinghai-strain from Febr.2005 is 030 per year !
that would make 600 for 1977-1997, 210 for 1997-2004, 810 for 1977-2004
For 1968 H3N2 the rate was also about 030 for the first 5 years,
but then it went down to ~020. I assume in new reassorted viruses
the mutation rate is higher because more mutations survive
when the sequences are not yet very optimal.
human H3N2, 1968(1972)-1998:492,594,510,1284,543,828,363,534
There are also some examples for preserved sequences in swine.
I'm not aware of such examples of low mutation rates
in human influenza except the "freeze" 1957-1977 in H1N1,
lab-escapes or vaccine strains.
schina
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