Biodiversità animale e sistemi zootecnici

Biodiversità animale e sistemi
zootecnici
Alessio Valentini
13/04/2010
Accademia Nazionale delle Scienze detta
dei XL
Comparisons of domesticated wild species (left of each pair) and their neverdomesticated close relatives (right) reveal the subtle factors that can derail domestication.
J. Diamond, Nature 2002
13/04/2010
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Rules for animal domestication
•a diet not easily supplied by humans (hence no domestic
anteaters),
•slow growth rate and long birth spacing (for example,
elephants and gorillas),
•nasty disposition (grizzly bears and rhinoceroses),
• reluctance to breed in captivity (pandas and cheetahs),
• lack of follow-the-leader dominance hierarchies (bighorn
sheep and antelope),
•and tendency to panic in enclosures or when faced with
predators (gazelles and deer, except reindeer)
13/04/2010
Accademia Nazionale delle Scienze detta
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13/04/2010
Accademia Nazionale delle Scienze detta
dei XL
The mystery of Etruscan origins: novel clues from Bos taurus mitochondrial DNA
Marco Pellecchia,1 Riccardo Negrini,1 Licia Colli,1 Massimiliano Patrini,1 Elisabetta Milanesi,1†
Alessandro Achilli,2 Giorgio Bertorelle,3 Luigi L Cavalli-Sforza,4 Alberto Piazza,5 Antonio Torroni,2
and Paolo Ajmone-Marsan1*
Proc Biol Sci. 2007 May 7; 274(1614): 1175–1179.
Fig. 2 Combination of enJSRV proviruses (retrotypes) in the domestic sheep
B. Chessa et al., Science 324, 532 -536 (2009)
Published by AAAS
Fig. 3 Genetic distances between sheep populations on the basis of enJSRVs insertion frequencies
B. Chessa et al., Science 324, 532 -536 (2009)
Published by AAAS
Lactose intolerance by region (African countries are only a rough guess).
Red indicates a high percentage of intolerance, green a low percentage.
Wikipedia.org
13/04/2010
Accademia Nazionale delle Scienze detta
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Approximate posterior density of region of origin for LP/dairying co-evolution.
Itan Y, Powell A, Beaumont MA, Burger J, Thomas MG, 2009 The Origins of Lactase Persistence
in Europe. PLoS Comput Biol 5(8)
13/04/2010
Accademia Nazionale delle Scienze detta
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Central Dogma of Genetics
11
Breeds of
cattle
Why so many colors?
Molecular causes of Mc1r loss-of-function
C33T
red chicken
(Takeuchi, 1996)
DG104
red cow
(Klungland, 1995)
DC183
yellow mouse
(Robbins, 1993)
S83F
chestnut horse
(Marklunk, 1996)
R306ter
Irish Setter
(Newton, 2000)
A240T
red pig
(Kijas, 1998)
R151C
red hair
(Rees, 1997)
Important genes affecting
production traits
 Leptin - fat deposition
 DGAT1 – milk production and fat
 BHGR – milk components
 Thyroglobulin - marbling
 Calpastatin - tenderness
 Calpain - tenderness
 Somatostatin -- marbling
Myostatin (double muscling)
Belgian blue
Double Muscling in cattle
Marchigiana
Piemontese
Effect of abolishing GDF8
expression
•
General increase in muscle
mass
– Muscular Hyperplasia
GDF8 +
• up to 86% increase in muscle
fibers
– and Hypertrophy
• up to 20% increase in fiber
diameter
GDF8 -
The way from DNA to
functional proteins is much
longer than envisaged by the
“central dogma”!
Control of Gene Expression
• Repression of
Transcription Mechanisms:
– Binding to
promoter elements
• Blocking assembly
of the
preinitiation
complex
Topic 8-2
20
Control of Gene Expression
• Repression of
Transcription Mechanisms:
– Inhibiting binding
or functioning of
transcriptional
activators
Topic 8-2
21
Control of Gene Expression
• Repression of Transcription
– DNA Methylation
• Methyl groups may be attached to cytosine
(C5 position)
– Methyltransferases
• Methyl groups provide a tag
• In mammals always part of a symmetrical
sequence
• Concentrated in CG-rich domains
– Often in promoter regions
• Methylation of promoter DNA highly
correlated with gene repression
Topic 8-2
22
Callipyge
• “Beautiful buttocks”
• A mutation which
arose in a Dorset Ram
• “Polar
Overdominance”
Polar overdominance
• Heterozygote expresses the phenotype but
neither homozygote does
• Heterozygote only expresses the phenotype if
the mutant gene is inherited from the father
Positional identification of genes influencing
muscle mass …
« Double-muscled » Belgian Blues:
MSTN KO
Hypermuscled Piétrains:
IGF2 upregulation
miRNA
biology
Callipyge sheep:
Ectopic DLK1 expression
polar overdominance
Hypermuscled Texel:
Patrocles mutation
A QTL affecting muscle mass maps to OAR2 …
Chromosome 2
Texel sheep produce normal levels of normal
MSTN mRNA
• Sequencing the MSTN ORF from
gDNA & cDNA:
– no polymorphism.
• Northern blot and qRT-PCR:
– no obvious qualitative or
quantitative difference.
Resequencing the MSTN gene identifies 20
non-coding SNPs …
3 Texels – 7 controls
G+6723G-A reveals one of « Kellis’s octamer
motifs » …
G
-central role of Dicer in RNAi
pathway
-cleaves 2nt-3´-overhangdsRNA; endogenous (premiRNA) and exogenous
dsRNA into miRNA and
siRNA
-products interact with RISC
for sequence-specific genesilencing
Genomic Sequencing
Launch: Dec. 2003
Expected Finish: Spring 2007
International Collaboration
–
–
–
–
–
–
–
NIH / NHGRI -- $25M
State of Texas – $10M
USDA -- $11M
Australia -- $1M
Genome Canada -- $5M
New Zealand -- $1M
Beef Councils (US, TX, SD) – $0.82M
Project Total = $53M
SNP Discovery in the Genome Age
Dominette
...AGCTTTAAGCCATACCTTAGGACATTACCTAGG
GCCATACCTTAGGACATTACCTAGGAGCTTTAAGCCATAC...
...AGCTTTAAGCCATACCTTAGGACATTACCTAGGAGCTTTAAGCCATA
...AGCTTTAAGCCATACCTTAGGACATTACCTAGGAGCTTTAAGCCATA
...AGCTTTAAGCCATACCTTAGGACATTACCTAGGAGCTTTAAGCCATA
...AGCTTTAAGCCATACCTTAGGACATTACCTAGGAGCTTTAAGCCATA
Consensus
...AGCTTTAAGCCATACCTTAGGACATTACCTAGGAGCTTTAAGCCATA
...AGCTTTAAGCCATACCTTAGGATATTACCTAGGAGCTTTAAGCCATA
Martha
SNP
Genomic selection
Training
EBV
Predicted
EBV
Gain from genomic selection
13/04/2010
Accademia Nazionale delle Scienze detta
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Cattle breed
Country
Period
Census
population
sizea
Effective
population
size (Ne)
Holstein
Denmark
1983-1992
-
68
Holstein
Germany
1999
≈ 2,200,000
52
Holstein
Denmark
1993-2003
≈ 3,700,000
49
Holstein
France
1988-1991 (?)
≈ 2,500,000
46
Holstein
USA
1999
≈ 8,500,000
39
Jersey
Denmark
1977-1991
-
87
Jersey
Denmark
1993-2003
≈ 640,000
53
Jersey
USA
1999
≈ 550,000
30
Danish red
Denmark
1977-1998
-
157
Danish red
Denmark
2001-2003
≈ 560,000
47
Japanese black
Japan
1986-1990
-
30
Japanese black
Japan
1993-1997
≈ 530,000
17
Montbéliarde
France
1988-1991 (?)
≈ 700,000
125
Abondance
France
1988-1991 (?)
≈ 65,000
106
Normande
France
1988-1991 (?)
≈ 800,000
47
Tarentaise
France
1988-1991 (?)
≈ 14,000
27
Reference
Sørensen et al.
2005
Koenig &
Simianer 2006
Sørensen et al.
2005
Boichard et al.
1996
Weigel 2001
Sørensen et al.
2005
Sørensen et al.
2005
Weigel 2001
Sørensen et al.
2005
Sørensen et al.
2005
Nomura et al.
2001
Nomura et al.
2001
Boichard et al.
1996
Boichard et al.
1996
Boichard et al.
1996
Boichard et al.
1996
Taberlet P, Valentini A., Rezaei Hr, Naderi S, Pompanon F, Negrini R, Ajmone-Marsan P. (2008). Are cattle, sheep, and
goats endangered species?. Molecular Ecology. vol. 17(1), pp. 275-284
13/04/2010
Accademia Nazionale delle Scienze detta
dei XL