What is Conservation Genetics? -- Application of genetics to preserve species as dynamic entities capable of coping with environmental change and encompasses:

• genetic management of small populationsgenetic management of small populations• resolution of taxonomic uncertaintiesresolution of taxonomic uncertainties• defining management units within speciesdefining management units within species• use of molecular genetic techniques in use of molecular genetic techniques in

forensics & understanding species biology.forensics & understanding species biology.

When a population or species disappears, all thegenetic information carried by that populationor species is lost!

When a contiguous population is fragmented intomany small populations, genetic diversity withineach may decay over time

“Gene pools are becoming diminished andGene pools are becoming diminished andfragmented into gene puddlesfragmented into gene puddles” (Thomas Foose, 1983)

Why Genetics?Why Genetics?

Evolution is the single most unifying organizationalconcept in all of biology and should play a prominent role in conservation as well.

Evolution is dynamic and change is expected.ecological systems are dynamic and generally notin equilibrium.

The best way to manage such dynamic systemsis a ConservationistConservationist rather than PreservationistPreservationistapproach.

Three biological reasons to believe genetics canmake important contribution to conservationbiology.

1. Fundamental theorem of natural selectiontells us that the rate of evolutionary changein a population is proportional to the amountof genetic diversity available.

Darwin-Wallace Theory of Natural SelectionDarwin-Wallace Theory of Natural Selection

If supplied with sufficient nutrients and protectionthe total population size will increase geometrically.However, due to high death rates, geometricincrease is not maintained indefinitely.

All species are variable

Darwin-Wallace Theory of Natural SelectionDarwin-Wallace Theory of Natural Selection

Those individuals with variations of characters thatbetter enable them to survive and reproduce will leave proportionally more offspring.

This results in the increase of the advantageouscharacters in the next generation.

2. There is a consensus among population geneticists that heterozygosity, or high geneticvariation within individuals or populations, is positively related to fitness.

3. The global pool of genetic diversity representsall the information for all biological processeson the planet.

Loss of such diversity will probably decreasethe ability of organisms to respond to environmental changes and discard informationpotentially useful to humans.

Basic problem linking genetics to conservation isthat small populations, whether in the wild orcaptivity, tend to lose genetic variation over time.

This loss of variation may well increase the probability of population extinction or reducedopportunities for future adaptation throughevolutionary change.

The basic thrust of conservation genetics and themessage to take from this course is:

We must maintain natural patterns of geneticWe must maintain natural patterns of geneticdiversity at many levels and thus preservediversity at many levels and thus preserveoptions for future evolution!!!options for future evolution!!!

Limitations of Genetics in Conservation BiologyLimitations of Genetics in Conservation Biology:

1. Application of genetics to conservation problemsis a young science that is still developing.

2. Many genetic techniques are not cheap andcan be misused or misapplied.

3. Plant and animal tissues must be obtained andproperly handled.

“Genetic factors do not figure among the fourmajor causes of extinction (the Evil Quartetthe Evil Quartet):overkill, habitat destruction and fragmentation,impact of introduced species, and secondary cascade effects”.

Thus, although genetic factors are major determinants of a populations long-term viability,conservationists can do more for a threatenedpopulation in the short-term by managing itsecology.

Conservation Genetics deals with the geneticfactors that affect extinction risk and geneticmanagement regimes required to minimize theserisks.

There are 11 major genetic issues in conservationbiology.

1. The deleterious effects of inbreeding onreproduction and survival (inbreeding depressioninbreeding depression)

2. Loss of genetic diversity & ability to evolve inresponse to environmental change.

3. Fragmentation of populations and reducedgene flow.

4. Random processes (genetic driftgenetic drift) overridingnatural selection as the main evolutionaryforce.

5. Accumulation and loss (purgingpurging) of deleteriousmutations.

6. Genetic adaptation to captivity & its adverseeffects on reintroduction success.

7. Resolving taxonomic uncertainties.

8. Defining management units within species.

9. Use of molecular genetic analyses in forensics.

10.Use of molecular genetic analyses to understandaspects of species biology

11.Deleterious effects of fitness that sometimesoccur as a result of outcrossing (outbreeding depressionoutbreeding depression).

How is genetics used to minimize extinction?

1. Reducing extinction risk by minimizinginbreeding and loss of genetic diversity.

2. Identifying populations of concern.

3. Resolving population structure

4. Resolving taxonomic uncertainties

5. Defining management units within species.

6. Detecting hybridization

7. Non-intrusive sampling for genetic analyses.

8. Defining sites for reintroduction.

9. Choosing the best populations for reintroduction.

10.Forensics.

11.Understanding species biology

Biodiversity -- the variety of ecosystems, species,populations within species and genetic diversitywithin species.

Biological diversity of planet is being rapidly Depleted due to direct and indirect consequencesOf humans.

Scale of this problem is enormous and has been Termed the “Sixth ExtinctionSixth Extinction” as its magnitudeIs comparable with that of the other five massExtinctions revealed in the geologic record.

Conservation genetics is motivated by the needto reduce current rates of extinction and topreserve biodiversity

Why Conserve Biodiversity? Because humansDerive many direct and indirect benefits fromThe living world, we have a stake in conservingBiodiversity for:

resources we useecosystem services it providespleasure we derive from living organismsethical reasons

Bioresources includes all food, many pharmaceuticals, clothing fibers, rubber & timberwith a value in billions of dollars annually.

About 25% of all pharmaceutical prescriptionsin the US contain active ingredients derived from plants.

The natural world contains many potentially useful novel resources: Ants contain novel antibiotics that are being investigated for use in human Medicine.

Ecosystem Services -- essential biological functionsThat are provided free of charge by living organismsAnd which benefit mankind such as:

Oxygen production by plantsClimate control by forestsNutrient cyclingNatural pest controlPollination of crop plants

These services have been valued at These services have been valued at $33 trillion/year or almost double the $18 trillion $33 trillion/year or almost double the $18 trillion yearly global national product!!!!yearly global national product!!!!

AestheticsAesthetics -- Humans derive pleasure fromliving organisms. This translates into directeconomic value.

Koalas are estimatedto contribute $70million annually to theAustralian tourismindustry.

EthicsEthics -- The ethical justifications forconserving biodiversity are simply that onespecies does not have the right to driveother species to extinction!

The IUCN (the World Conservation Union)Recognizes the need for conservation at theLevels of:

genetic diversityspecies diversityecosystem diversity

Based on the principles of population biology, in1996 the IUCN defined criteria to classifyspecies into:

Critically EndangeredCritically EndangeredEndangeredEndangeredVulnerableVulnerableLower RiskLower RiskExtinctExtinctExtinct in the wildExtinct in the wildConservation DependentConservation DependentNear ThreatenedNear ThreatenedData deficientData deficient

Information used by IUCN to decide whether species fall into critically endangered, endangered, or vulnerable categories. A species falling within any of categories A-E in the critically endangered column is defined as critically endangered. Similar rules apply to endangered and vulnerable categories.

Criteria (any 1 of A-E) Criteria (any 1 of A-E) Critically EndangeredCritically Endangered EndangeredEndangered VulnerableVulnerable

A. Actual or projected 80% decline over past 10 50% 20%reduction in pop. size or 3 generations

B. Extent of occurrence or < 100 km2 5000 km2 20,000 km2

areas of occupancy < 10 km2 and any 2 of: 500 km2 2,000 km2

(i) severely fragmented or 5 locations 10 locationsknown to exist at single locality(ii) continuing declines, and(iii) extreme fluctuations

C. Population numbering < 250 mature individuals and < 2,500 <10,000an estimated continuing decline

D. Population estimated < 50 mature individuals < 250 < 1,000to number

E. Quantitative analysis at least 50% within 10 yrs or 20% in 20 yrs 10% in 100showing the probability 3 generations, whichever is or 5 generations yrsof extinction in the the longerwild.

It is of critical importance to defineendangerment as it is the basis for legal protection for species.

Most countries have Endangered Species Actsthat provide legal protection for threatenedspecies and usually require the formulation ofrecovery plans.

Additionally, trade in threatened species is banned by countries that have signed theConvention on International Trade in EnangeredConvention on International Trade in EnangeredSpecies (CITES).Species (CITES).

Small populations suffer from inbreeding & lossof genetic diversity resulting in elevatedextinction risks.

Consequently, a major objective of genetic management is to minimize inbreeding & loss ofgenetic diversity.