Genetic Erosion and Genetic Pollution : Some thoughts Luigi Guarino Secretariat of the Pacific Community (SPC) Suva, Fiji Nigel Maxted University of Birmingham Birmingham, UK

Talk Objectives Review the approaches to the assessment and prediction of genetic erosion Review the approaches to the assessment and prediction of genetic erosion Distinguish between taxonomic and genetic erosion Distinguish between taxonomic and genetic erosion Establish tentative indicators of genetic erosion Establish tentative indicators of genetic erosion Some initial thoughts on genetic pollution Some initial thoughts on genetic pollution Establish tentative indicators of genetic pollution Establish tentative indicators of genetic pollution Prioritising CWR List in Relation to Genetic Erosion and Pollution Prioritising CWR List in Relation to Genetic Erosion and Pollution

Genetic Erosion Definition – “Permanent reduction in the number, evenness and distinctness of alleles, or combinations of alleles, of actual or potential agricultural importance in a defined geographical area” (FAO, 1999) Definition – “Permanent reduction in the number, evenness and distinctness of alleles, or combinations of alleles, of actual or potential agricultural importance in a defined geographical area” (FAO, 1999) Decrease/loss in (useful?) genetic diversity in a given area over a given time period Decrease/loss in (useful?) genetic diversity in a given area over a given time period –“X genetic diversity was lost at place Y between time A and time B in the past”  Need to be able to measure genetic diversity  Need to define the geographic area  Need to be able to make comparisons in time –“X genetic diversity may be lost at place Y between now and a time in the future”  Need to extrapolate in time and space  Need to quantify confidence of prediction Population change is universal (applies to all biodiversity), can be natural, there is a need to distinguish between Population change is universal (applies to all biodiversity), can be natural, there is a need to distinguish between –Natural changes –Anthropogenic related population changes

Genetic Erosion Why genetic diversity is important Why genetic diversity is important –Maintain viability and evolutionary potential of individuals / populations / species –Direct use by humankind Genetic erosion associated with ex situ collection or in situ populations Genetic erosion associated with ex situ collection or in situ populations Identification of indicators: Identification of indicators: 1.Prophylactic 2.Assessment 3.Prediction

Prophylactic Approach Loss of species (= taxonomic erosion) Loss of species (= taxonomic erosion) Difficult to estimate, but Difficult to estimate, but –IUCN ( estimate 11,000 species are imminently threatened with extinction –Reduction in numbers of crop species (UK Forages; Sackville-Hamilton, 1999) Year Number of grass species1362 Number of legume species741 Number of other dicot species450 Total24153 Taxonomic erosion must involve loss of genetic diversity as well Taxonomic erosion must involve loss of genetic diversity as well

Prophylactic Approach Loss of genetic diversity (=genetic erosion) Loss of genetic diversity (=genetic erosion) –Extremely difficult to quantify, evidence is often anecdotal (FAO Prague Meeting, 1999) or nomeclaturally based as for potato landraces on Chilean island of Chiloe (Ochoa, 1975) –Quantifying loss examples:  Akimoto et al. (1999) Oryza rufipogon from Thailand sampling 1985 & 1994 same populations, allozyme analysis = severe decline, rampant genetic pollution (1996 extinct!)  De Oliveira & Martins (2002) ipecac from Brazil – indirect and comparative using Guarino (1995) model YearLandraces number ≈

Prophylactic Approach –Maxted et al. (1997) guesstimate 25-35% of plant genetic diversity could be lost over the next 12 years  100% of extinct species  ?% of remaining extant species –Largely anecdotal or nomeclaturally based arguments for genetic erosion: urgent need for rigorous testing (Brush, 1999)

Prophylactic Approach Even though imprecise there is a devastating lost of biodiversity at species and genetic levels, and linked to socio-economic use of diversity, post Vavilov gave rise to rush to collect in 20 th Century Even though imprecise there is a devastating lost of biodiversity at species and genetic levels, and linked to socio-economic use of diversity, post Vavilov gave rise to rush to collect in 20 th Century Conservation has a real cost, so must be efficient Conservation has a real cost, so must be efficient –No overall estimate of PGR conservation costs –Cost of ex situ gene bank conservation alone = US $30.5 million per year (Hawkes et al., 2001) –Ex situ gene bank conservation is only 1% of total conservation costs (Cohen et al., 1991) –Conservation is expensive! Use for conservation products Use for conservation products –However, estimate of use of PGR = US $ billion per year ten Kate and Laird (1999)

Prophylactic Approach The need for a prophylactic approach is self evident The need for a prophylactic approach is self evident –Conserve now to ensure use for tomorrow  Protection area focus on in situ ‘hotspots’  Ex situ duplication  Increase ‘value’ of landraces (value-added)  Conservation legislation (national, regional, global)  Raise public awareness (professional and general public) in the: –value of nature –uses of nature / genetic diversity –Need for conservation

Erosion Assessment Direct (measurement of past and current genetic diversity and relative changes) Direct (measurement of past and current genetic diversity and relative changes) –Genetic diversity assessment applying molecular techniques  Temporal - compare population’s genetic diversity over a set time period, re-sampling ex situ conserved populations  Spatial - compare different population’s genetic diversity at the same time –Phenotypic variation

Erosion Assessment Indirect – any ‘proxy’ factor influencing change in genetic diversity) Indirect – any ‘proxy’ factor influencing change in genetic diversity) –Population characteristics assessment  size  dispersal,  fecundity, etc. –Ethnographic assessment  IK surveys –Taxon specific assessment  Taxonomic diversity assessment (vars., races)  Nomenclatural diversity assessment (landrace names)  Taxon characteristics (e.g. outbreeders)

Taxon Specific Genetic Erosion Species with a restricted geographical and ecological range Species with a restricted geographical and ecological range Species restricted to natural habitats subject to destruction, degradation and fragmentation Species restricted to natural habitats subject to destruction, degradation and fragmentation Species poorly adapted to their niche and easily displaced by competition from more aggressive or alien species Species poorly adapted to their niche and easily displaced by competition from more aggressive or alien species Species found in anthropogenic or disturbed habitats Species found in anthropogenic or disturbed habitats Species growing in marginal or very localised anthropogenic environments that are vulnerable to changes in agricultural practices or land use Species growing in marginal or very localised anthropogenic environments that are vulnerable to changes in agricultural practices or land use Species growing in environments subject to regular natural or human- directed disasters. Species growing in environments subject to regular natural or human- directed disasters. Species subject to wild harvesting, over-exploitation and incidental take Species subject to wild harvesting, over-exploitation and incidental take

Erosion ‘Proxy’ Assessment –Environment / habitat specific assessment – any factor likely to result in genetic erosion  Environmental disturbance or change (local, national, global)  Natural or artificial habitat loss or modification (local, national, global)  Over-exploitation (local, national, global)  Competition from exotic species (local)  Disturbance (local)  Disease (local)  Limited distribution (local)

Prediction of Erosion based on ‘Proxy’ factors Guarino Model for quantifying the threat of genetic erosion – 24 questions: 1)General a)Taxon distribution -Rare10 -Locally common 5 -Widespread or abundant 0 b)Drought -Known to have occurred in two or more consecutive years10 -Occurring on average one or more times every ten years, but not in consecutive years 5 -Occurring less than once every ten years 0 c)Flooding -Area known to be very flood prone10 -Area not known to be flood prone 0

Prediction of Erosion IUCN Red List Categories IUCN Red List Categories Do the categories require adaptation for PGR / CWR use? Do the categories require adaptation for PGR / CWR use?

Measures to Predict Erosion Direct Direct –Molecular analysis of past and current genetic diversity Indirect Indirect –Ecogeographic / ethnographic projection of genetic erosion based on past experience  Use community-based space/time comparisons to identify factors causative of - or at least correlated with - with erosion  get taxon or regional based data for these and/or their proxies now and at time X in the past  use GIS to map risk of genetic eroson (modeling) for period time X  now then project from now  time Y  validate past risk with observed genetic erosion  refine model for the future

Environment / Habitat Specific Genetic Erosion Environment / habitat specific assessment – any factor likely to result in genetic erosion Environment / habitat specific assessment – any factor likely to result in genetic erosion –Environmental disturbance / habitat loss / fragmentation  Drainage work  Dam building  Agricultural development programmes  Road construction, etc. –Country-wide studies (based on secondary data)  Ecogeography  GIS  Remote sensing  Aerial photography

Priority areas for collecting wild Gossypium in Africa Climates associated with high diversity High risk of genetic erosion – –soil degradation – –cattle density – –human population growth Collecting gaps High accessibility

Priority areas for collecting wild Arachis germplasm in Bolivia Data sources USDA, CIAT, FAN, WCMC Arachis climatesArachis climates Arachis diversity climatesArachis diversity climates Collecting gapsCollecting gaps Distance from protected areasDistance from protected areas Risk of genetic erosionRisk of genetic erosion population densitypopulation density soil degradationsoil degradation proximity to roads, new gas pipeline etc.)proximity to roads, new gas pipeline etc.)

The information pyramid Aggregating information Detailed local information  national  global level Detailed local information  national  global level Affects quantity and quality of information passed along to decision-makers Affects quantity and quality of information passed along to decision-makers Can have a significant effect on the decision-making outcome Can have a significant effect on the decision-making outcome Need to establish a baseline understanding of genetic diversity for future comparison Need to establish a baseline understanding of genetic diversity for future comparison

12 Genetic Erosion Indicators 1.Relative taxon / variety rarity 2.Relative genetic diversity 3.Extent of occurrence / area of occupancy 4.Population size (< 5000), number and isolation 5.Degree and manner of socio- economic use 6.Geographic location relative to urban environment 7.Vulnerability to agricultural changes 8.Vulnerability to natural disaster 9.Presence in protected areas 10.Rare or restricted habitats 11.Threatened habitats 12. Application of complementary conservation studies (ex situ) To be applied at national, regional and global levels To be applied at national, regional and global levels

IUCN Extent of occurrence / Area of occupancy

Tools to help ID Genetic Erosion Direct / absolute Direct / absolute –Genetic diversity studies –Phenotypic characterisation –Regular grid of permanent sites to act as a baseline (Serwinski, 1999) Indirect / deductive Indirect / deductive –Ecogeographic surveys –GIS / remote sensing / aerial photography –Ethnographic surveys –… Primarily indirect / deductive ? Primarily indirect / deductive ?

Genetic Pollution More than just GMO contaminants! More than just GMO contaminants! France wild perennial ryegrass show expected pattern of increasing genetic distance with increasing geographical distance (Monestiez et al 1994) France wild perennial ryegrass show expected pattern of increasing genetic distance with increasing geographical distance (Monestiez et al 1994) UK uncultivated wild grass species Agrostis curtisii shows a similar pattern but wild perennial ryegrass has lost all trace of a positive relationship between genetic distance and geographical distance (Warren et al., 1998) UK uncultivated wild grass species Agrostis curtisii shows a similar pattern but wild perennial ryegrass has lost all trace of a positive relationship between genetic distance and geographical distance (Warren et al., 1998) SpeciesLolium perenneAgrostis curtisii Regression coefficient for F ST on distance-1.05 x x Significance**** r2r2 1.9%7.0%

Genetic Pollution Introduction of alien genetic diversity into a host genome Introduction of alien genetic diversity into a host genome –“X genetic diversity from the alien species A was introduced into the genome of the host species B”  Deliberate (i.e. Breeding = introgression as a result of conscious human actions = beneficial)  Natural (i.e. introgression = beneficial?)  ‘Accidental’ (i.e. introgression as a result of unconscious human actions = potentially harmful) = genetic pollution –“X genetic diversity from the alien species A may be introduced into the genome of the host species B”  Need to extrapolate in time and space  Need to quantify confidence of prediction

‘Accidental’ Genetic Pollution Need to be able to assess changes in genetic diversity, identify alien diversity Need to be able to assess changes in genetic diversity, identify alien diversity –Molecular techniques  Looking for cultivar markers in landrace or wild species e.g. 35% of maize landraces in Mexico have transgenic DNA  Numerous studies of gene flow stimulated by GMO debate! Avoid by geographical isolation, supra-pollination proximity of alien and host species Avoid by geographical isolation, supra-pollination proximity of alien and host species Identify species with propensity for genetic pollution Identify species with propensity for genetic pollution

Propensity for Genetic Pollution Species geographically close to the polluting species Species geographically close to the polluting species –Sympatric –Out-breeders Closely taxonomically related species to crops! Closely taxonomically related species to crops! –Crop are by definition a hotch-potch of alien genetic diversity –Crops may have been genetically modified Gene pool and taxon group Gene pool and taxon group –GP1b, GP2 –TG1b, TG2, TG3, TG4

Conclusion Prophylactic approach is always preferable as erosion and pollution cost money! Prophylactic approach is always preferable as erosion and pollution cost money! It is possible to use indicators to assess comparative probability of genetic erosion / genetic pollution and so prioritise conservation action It is possible to use indicators to assess comparative probability of genetic erosion / genetic pollution and so prioritise conservation action Tools are being developed for predicting genetic erosion, if not genetic pollution Tools are being developed for predicting genetic erosion, if not genetic pollution PGR Forum provides an opportunity to identify indicators and help meet the CBD COP 2010 targets! PGR Forum provides an opportunity to identify indicators and help meet the CBD COP 2010 targets!

Recommendations for Prioritising CWR List in Relation to Genetic Erosion and Pollution Highest priority Highest priority –Taxon related to crops GP1b / GP2 and TG1b, TG2, TG3, TG4 –Rare taxa with low population numbers, disparate populations, etc. –Taxa with unique genetic diversity –Taxa restricted to threatened habitats –Taxa vulnerability to agricultural changes Medium priority Medium priority –Wild harvested species –Taxa restricted to locations near urban centres –Taxa restricted to rare or restricted habitats –Taxa vulnerability to natural disaster Lower priority Lower priority –Taxa no present in protected areas –Taxa not duplicated in ex situ facilities ?Does rampant genetic erosion / genetic pollution question the validity of in situ conservation of CWR, if crop CWR introgression is widespread and genetic diversity is being eroded so quickly?