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Conservation genetics of cattle,
sheep, and goats
Pierre Taberlet
Laboratoire d'Ecologie Alpine, CNRS UMR 5553
Université Joseph Fourier, Grenoble, France
Conservation genetics of
cattle, sheep, and goats
•! Introduction on conservation genetics
•! History of cattle, sheep, and goats
•! Conservation issues
–! The FAO/UNEP strategy
–! Facts
–! Threats on genetic resources
•! Towards a sustainable management of
genetic resources
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Conservation genetics of
cattle, sheep, and goats
•! Introduction on conservation genetics
•! History of cattle, sheep, and goats
•! Conservation issues
–! The FAO/UNEP strategy
–! Facts
–! Threats on genetic resources
•! Towards a sustainable management of
genetic resources
Conservation
genetics
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Effective population size (Ne)
•! Definition –! "the number of breeding individuals in an idealized
population that would show the same amount of
dispersion of allele frequencies under random genetic
drift or the same amount of inbreeding as the population under consideration" (Wright 1931, 1938)
•! The 50/500 rule-of-thumb (Franklin 1980) –! In the short term Ne should not be less than 50
(increased probability of extinction because of genetic
effects)
–! In the long term Ne should not be less than 500
The
extinction
vortex
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The
extinction
vortex
Extinction
Conservation genetics of
cattle, sheep, and goats
•! Introduction on conservation genetics
•! History of cattle, sheep, and goats
•! Conservation issues
–! The FAO/UNEP strategy
–! Facts
–! Threats on genetic resources
•! Towards a sustainable management of
genetic resources
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Farm animal history
present 5,000 BP 10,000 BP
Domestication of cattle, sheep,
and goats in Middle East
Cattle domestication (1)
•! Wild ancestor now extinct: auroch (Bos primigenius)
•! Domestication: 10500 BP (Helmer et al. 2005)
•! For domestic cattle, the common usage accepts two taxa
(Bos taurus, B. indicus)
•! Mitochondrial DNA polymorphism: two main lineages
corresponding to two domestication events (Loftus et al.
1994; Bradley et al. 1996)
•! Eighty four percent of the mtDNA variation is partitioned
among continents (Bradley et al. 1996)
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Sheep
A
B
!"
!"!!#
!"!!#
CattleBos indicus
Bos taurus
!"!$
GoatD
F
C
B
A G
Cattle domestication (2) Mitochondrial DNA polymorphism
85% among continents
Sheep domestication (1)
•! Wild ancestor(s): Ovis orientalis
•! Domestication: 10500 BP (Peters et al. 2005)
•! Domestic species: O. aries
•! Mitochondrial DNA polymorphism: four main lineages (Tapio et al. 2006)
•! Thirty five percent of the mtDNA variation is partitioned among continents (Townsend 2000)
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Sheep
A
B
!"
!"!!#
!"!!#
CattleBos indicus
Bos taurus
!"!$
GoatD
F
C
B
A G
Sheep domestication (2) Mitochondrial DNA
polymorphism 35% among continents
No relationship
with breeds
Goat domestication (1)
•! Wild ancestor: Bezoar (Capra aegagrus)
•! Domestication: 10500 BP (Peters et al. 2005)
•! Domestic species: Capra hircus
•! Mitochondrial DNA polymorphism: six main lineages (Naderi et al. 2007)
•! Ten percent of the mtDNA variation is partitioned among continents (Luikart et al. 2001)
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Sheep
A
B
!"
!"!!#
!"!!#
CattleBos indicus
Bos taurus
!"!$
GoatD
F
C
B
A G
Goat domestication (2)
Mitochondrial DNA
polymorphism 10% among continents
No relationship with breeds
Domestication in the Fertile Crescent,
about 10,500 years ago
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Domestication of cattle,
sheep, and goats
•! Multiple maternal origins
•! High level of nuclear DNA polymorphism
•! No evidence of bottleneck during the domestication
(sheep and goats)
•! Maybe a bottleneck during the domestication of
cattle, but evidence of introgression from aurochs
later on
•! Very large gene pools on which human induced-
selection was acting to produce the diversity of
breeds we observe today
Farm animal history
present 5,000 BP 10,000 BP
Domestication of cattle, sheep,
and goats in Middle East
Spread of cattle, sheep,
and goats in Europe
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Dispersal from the
domestication centers
10,500
8,200
7,100
7,600
7,400
7,500
8,000
Danubian route
Mediterranean route
Farm animal history
present 5,000 BP 10,000 BP
Domestication of cattle, sheep,
and goats in Middle East
Emergence of the breed concept Spread of cattle, sheep,
and goats in Europe
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Paulus Potter (1625-1654)
Anthonie van Borssum
(1630/31-1677)
Rosa Bonheur (1822-1899): 1849
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The breed concept
•! About 200 years ago
•! At the same time that the industrial
revolution
•! Standardization of phenotypes and
performances
•! Corresponds to the fragmentation of the
initial gene pool
Farm animal history
present 5,000 BP 10,000 BP
Domestication of cattle, sheep,
and goats in Middle East
Emergence of the breed concept
Beginning of intensive selection
Spread of cattle, sheep,
and goats in Europe
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Artificial insemination
Strong reduction of the effective population size
•! About 10000 years ago: farmers started to control the reproduction of their farm animals in a traditional way
•! About 200 years ago (2% of the history): standardization of the color, morphology, and performance
•! Reproduction among different phenotypes was seriously reduced
•! About 50 years ago (0.5% of the history): the selection pressures strongly increased
Summary of the history
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Conservation genetics of
cattle, sheep, and goats
•! Introduction on conservation genetics
•! History of cattle, sheep, and goats
•! Conservation issues
–! The FAO/UNEP strategy
–! Facts
–! Threats on genetic resources
•! Towards a sustainable management of
genetic resources
The FAO/UNEP strategy in
the seventies •! The first joint project was launched in 1974 with the title
"Conservation of animal genetic resources (pilot study)". A survey of
the cattle breeds of Europe and the Mediterranean countries revealed
that of 149 indigenous breeds in this area only 33 are holding their
own and the others are declining in numbers. For the rest of the
world, and the non-bovine species in Europe, the report gives a brief
survey of breeds which appear to be in danger of eventual extinction.
•! The FAO/UNEP collaborative project on the Conservation of Animal Genetic Resources, which is now coming to an end, has clearly
shown the growing need for strengthening activities on the evaluation
of animal genetic resources at the national level and for monitoring
genetic changes. This need is further highlighted by the growing
evidence that critical shortages of suitable livestock resources have
appeared over the last decade in a number of regions.
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Current status Cattle Sheep Goats
Population size (billion) 1.4 1.1 0.7
Current number of breeds 1224 1313 570
Number of extinct breeds 254 181 17
% of extinct breeds 17 12 3
!"#$%&'()*'*+%),-."!%/01112%
Current status Cattle Sheep Goats
Population size (billion) 1.4 1.1 0.7
Current number of breeds 1224 1313 570
Number of extinct breeds 254 181 17
% of extinct breeds 17 12 3
!"#$%&'()*'*+%),-."!%/01112%
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Current status Cattle Sheep Goats
Population size (billion) 1.4 1.1 0.7
Current number of breeds 1224 1313 570
Number of extinct breeds 254 181 17
% of extinct breeds 17 12 3
!"#$%&'()*'*+%),-."!%/01112%
Current status Cattle Sheep Goats
Population size (billion) 1.4 1.1 0.7
Current number of breeds 1224 1313 570
Number of extinct breeds 254 181 17
% of extinct breeds 17 12 3
!"#$%&'()*'*+%),-."!%/01112%
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Threats on industrial breeds (1)
•! Artificial insemination strongly decreases the
genetic diversity
•! Germany: Ne = 52 for Holstein
•! France: Ne = 46 for Holstein
•! France: Ne = 27 for Tarentaise
•! Japan: Ne = 17 for Japanese Black
Threats on industrial breeds (2)
•! Emergence of new genetic diseases –!Bovine leukocyte
adhesion deficiency
–!Achondroplasia
–!Complex vertebral malformation (CVM)
•! Rapid decline in fertility –!USA, 1951: 65%
–!USA, 1996: 40%
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Threats on industrial breeds (3)
•! Introgression from highly productive breeds
•! New selection pressures (e.g. on coat colour)
Abondance
Montbéliarde
Threats on traditional breeds •! Already extinct: 17% of cattle breed and 12%
of sheep breed
•! Often low population size, with problem of
inbreeding
•! Competition with industrial breeds
•! Crossbreeding with industrial breeds
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In a few decades, we might lose
most of the highly valuable genetic
resources that humanity has
gradually selected over the past
10,000 years
Conservation genetics of
cattle, sheep, and goats
•! Introduction on conservation genetics
•! History of cattle, sheep, and goats
•! Conservation issues
–! The FAO/UNEP strategy
–! Facts
–! Threats on genetic resources
•! Towards a sustainable management of
genetic resources
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Towards a sustainable
management of genetic resources
•! Better characterization at the genetic level –! Problem of the ascertainment bias of microsatellites
and SNPs
–! Availability of whole genome sequences
–! Wild relatives / traditional breeds from the
domestication centre
•! Implementation of conservation strategies –! Genomic selection taking into account biodiversity
–! In the short term, very important to monitor the spread
of industrial breeds
–! The socio-economic aspect is crucial
Thank you for your attention
© Arcangelo Gentile