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flu-evolution in mallards is different from that in poultry or mammals
flu in mallards (and pintails,shovelers,teals,widgeons,guillemots,...)
have an almost fixed amino-acid sequence in the inner segments.
It presumably dominantly spreads by water and often developes fewer
nucleotide mutations as well.
So the calculations to examine most-recent-common-ancestor-dates
from mallard-sequences are to be taken carefully.
You often won't see the typical mutation-acquiring behaviour that
we are used to see from mammalean or poultry flu.
(see e.g. the thread about slow evolution in Chinese birds)
flu usually goes from mallards to other species, where it my set foot
and evolve (i.e. in the inner segments) separately for decades,centuries
and then die out, to get replaced by new (mallard-) strains.
We have no example that flu went back from poultry or mammals
to mallards in an evolution changing manner.
Mallards maintain their own, fundamental, index-close sequences
in the inner segments and a big variety in the 16 HAs and 9 NAs
and frequent reassortments. Occasionally (~~once per century ?)
west-mallard-flu (America) mixes with East-mallard-flu (Europe,Asia,
Oceania,Africa), but typically they are separated
These mixing events are potentially dangerous in forming
reassortments and new pandemic strains.
--------------------------------------------
searching pubmed for influenza,evolution,mallards
-----------------------------------------------------------
Phylogenetic analyses confirm two mitochondrial mallard clades. Genetic differentiation
within Eurasia and North-America is low, on a continental scale, but large differences
occur between these two land masses (F(ST) = 0.51).
a split between Eurasia and North-America 43,000 to 74,000 years ago
and strong population growth (~100fold) since then and little migration
(not statistically different from zero).
Based on this first complete assessment of the mallard's world-wide population genetic
structure we confirm that no more than two mtDNA clades exist. Clade A is characteristic
for Eurasia, and clade B for North-America although some representatives of clade A are
also found in North-America.
---------------------------------------------------
(Minnesota,H3N8,H4N6)
The viruses persisted in water for an extended time period at constant temperature
(several weeks) but infectivity rapidly reduced under multiple freeze-thaw cycles
----------------------------------------------------
A/mallard/Poland/446/09 (detected in December 2009) shared a recent common ancestor with
A/mallard/Poland/41/09 (isolated in February 2009) in relation to HA and PB1 genes, with
A/mallard/Poland/16/09 (found in January 2009) regarding NA and NS genes, and with
A/mallard/Poland/01/08 (recovered in December 2007) as regards the NS gene. Interestingly,
A/mallard/Poland/16/09 and A/mallard/Poland/446/09 were isolated at the same sampling site almost
exactly 1 year apart, which points to resident population of mallards (and other resident waterfowl)
---------------------------------------------------------------
they should test normal current human-flu viruses HA,NA, also H5N1 and the 6 inner segments from
the mallard-index in ferrets
5,1,3,2,1,1 A/NL/219/2003(H7N7)
8,7,10,9,7,5 A/BM/1/1918(H1N1)
--------------------------------------------------------------------------------------
A/Mallard/MN/Sg-00169/2007 (H3N8); A/Mallard/MN/Sg-00219/2007 (H4N8); A/Mallard/MN/Sg-00170/2007 (H6N1); A/Mallard/MN/Sg-00107/2007 (H6N2); A/Green-winged teal/MN/Sg-00197/2007 (H6N8) (referred to hereafter as their respective subtype). Relative abundance of the five virus subtypes (i.e. prevalence ± 95% confidence intervals) in the waterfowl population at the sampling site was 22.5 ± 9.7% (H3N8), 9.9 ± 6.9% (H6N1), 5.6 ± 5.4% (H6N2), 2.8 ± 3.9% (H6N8) and 1.4 ± 2.7% (H4N8) (cf. [27] for details).
13,3322,0,2,7,2,-,2
23,3365,5,3,6,2,1,6
13,3295,1,2,8,1,-,-*
15,3298,0,4,6,2,-,-*
18,3335,2,2,4,1,7,-
--------------------------------------------------------
flu in mallards (and pintails,shovelers,teals,widgeons,guillemots,...)
have an almost fixed amino-acid sequence in the inner segments.
It presumably dominantly spreads by water and often developes fewer
nucleotide mutations as well.
So the calculations to examine most-recent-common-ancestor-dates
from mallard-sequences are to be taken carefully.
You often won't see the typical mutation-acquiring behaviour that
we are used to see from mammalean or poultry flu.
(see e.g. the thread about slow evolution in Chinese birds)
flu usually goes from mallards to other species, where it my set foot
and evolve (i.e. in the inner segments) separately for decades,centuries
and then die out, to get replaced by new (mallard-) strains.
We have no example that flu went back from poultry or mammals
to mallards in an evolution changing manner.
Mallards maintain their own, fundamental, index-close sequences
in the inner segments and a big variety in the 16 HAs and 9 NAs
and frequent reassortments. Occasionally (~~once per century ?)
west-mallard-flu (America) mixes with East-mallard-flu (Europe,Asia,
Oceania,Africa), but typically they are separated
These mixing events are potentially dangerous in forming
reassortments and new pandemic strains.
--------------------------------------------
searching pubmed for influenza,evolution,mallards
-----------------------------------------------------------
Phylogenetic analyses confirm two mitochondrial mallard clades. Genetic differentiation
within Eurasia and North-America is low, on a continental scale, but large differences
occur between these two land masses (F(ST) = 0.51).
a split between Eurasia and North-America 43,000 to 74,000 years ago
and strong population growth (~100fold) since then and little migration
(not statistically different from zero).
Based on this first complete assessment of the mallard's world-wide population genetic
structure we confirm that no more than two mtDNA clades exist. Clade A is characteristic
for Eurasia, and clade B for North-America although some representatives of clade A are
also found in North-America.
---------------------------------------------------
(Minnesota,H3N8,H4N6)
The viruses persisted in water for an extended time period at constant temperature
(several weeks) but infectivity rapidly reduced under multiple freeze-thaw cycles
----------------------------------------------------
A/mallard/Poland/446/09 (detected in December 2009) shared a recent common ancestor with
A/mallard/Poland/41/09 (isolated in February 2009) in relation to HA and PB1 genes, with
A/mallard/Poland/16/09 (found in January 2009) regarding NA and NS genes, and with
A/mallard/Poland/01/08 (recovered in December 2007) as regards the NS gene. Interestingly,
A/mallard/Poland/16/09 and A/mallard/Poland/446/09 were isolated at the same sampling site almost
exactly 1 year apart, which points to resident population of mallards (and other resident waterfowl)
---------------------------------------------------------------
they should test normal current human-flu viruses HA,NA, also H5N1 and the 6 inner segments from
the mallard-index in ferrets
5,1,3,2,1,1 A/NL/219/2003(H7N7)
8,7,10,9,7,5 A/BM/1/1918(H1N1)
--------------------------------------------------------------------------------------
A/Mallard/MN/Sg-00169/2007 (H3N8); A/Mallard/MN/Sg-00219/2007 (H4N8); A/Mallard/MN/Sg-00170/2007 (H6N1); A/Mallard/MN/Sg-00107/2007 (H6N2); A/Green-winged teal/MN/Sg-00197/2007 (H6N8) (referred to hereafter as their respective subtype). Relative abundance of the five virus subtypes (i.e. prevalence ± 95% confidence intervals) in the waterfowl population at the sampling site was 22.5 ± 9.7% (H3N8), 9.9 ± 6.9% (H6N1), 5.6 ± 5.4% (H6N2), 2.8 ± 3.9% (H6N8) and 1.4 ± 2.7% (H4N8) (cf. [27] for details).
13,3322,0,2,7,2,-,2
23,3365,5,3,6,2,1,6
13,3295,1,2,8,1,-,-*
15,3298,0,4,6,2,-,-*
18,3335,2,2,4,1,7,-
--------------------------------------------------------
,mallards(asymptomatic)
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