Conservation genetics applies genetic methods to preserve biodiversity and avoid species extinction. It studies levels of genetic diversity within and among populations and species. Small, isolated populations are vulnerable to loss of diversity through genetic drift, inbreeding, and reduced gene flow. Ex situ conservation involves captive breeding programs and gene banks, while in situ conservation preserves species in their natural habitats through parks and reserves. Population augmentation also aims to boost small populations but risks outbreeding depression if not done carefully. Conservation genetics uses an interdisciplinary approach to understand and preserve genetic diversity in threatened species.

1. BY: PAULA MARIE M. LLIDO
BSED – 3 BIOLOGICAL SCIENCES
CONSERVATION
GENETICS
CHAPTER 24

2. understand the dynamics of genes in populations
principally to avoid extinction.
applies genetic methods to the conservation
and restoration of biodiversity.
CONSERVATION GENETICS
CLIMATE CHANGE
THREATENED SPECIESGMOs
INCREASING HUMAN
POPULATION SPECIES
EXTINCTION

3. LEVELS OF GENETIC
DIVERSITY
•

4. INTERSPECIFIC
DIVERSITY
INTRASPECIFIC
DIVERSITYDiversity from different species present in an ecosystem
(ex. Rainforest with different plant and animal species)

5. INTERSPECIFIC
DIVERSITY
INTRASPECIFIC
DIVERSITY
diversity within same species
(ex. Squirrel population)
INTRAPOPULATION DIVERSITY INTERPOPULATION DIVERSITY
Genetic variation occurring
within a single population of
same species
Genetic variation occurring
between different population of
same species (ex. Squirrel Pop A and B)

6. INTRAPOPULATION
OR
INTERPOPULATION
DIVERSITY?
INTERSPECIFIC OR INTRASPECIFIC
DIVERSITY?

7. LOSS OF GENETIC
DIVERSITY
• Excessive hunting or harvesting
• Habitat loss
cause – human activities
effect – POPULATION FRAGMENTATION
• In domesticated species, abandoning
cultivation of local types, which may
disappear
HEEELP!!!

8. IDENTIFYING GENETIC DIVERSITY
(DNA Analysis Techniques)
• Short Tandem Repeats (STRs) / microsatellites
(ex. 3 remaining population of endangered plants
silversword found only in Hawaii)
• PCR-based DNA fingerprinting
(ex. Illegal ivory smuggled and elephant droppings)
• mtDNA
(ex. Turtle meat (for consumption) is actually an alligator’s
meat!)

9. Population Size Has a Major Impact on
Species Survival
• < 100 individuals – extremely sensitive
to genetic drift, inbreeding, and
reduction of gene flow.
• 100,000 individuals – long-term
sustainability.
• Effective population size – # of
individuals in population having the
equal probability of contributing
gametes to the next generation
Also influenced by
FLUCTUATION

10. • Population bottleneck –
TYPES OF GENETIC DRIFT

11. Genetic Effects are More Pronounced in
Small, Isolated Populations
Small isolated populations, such as those
found in threatened and endangered species
or produced by population fragmentation,
are especially vulnerable to genetic drift,
inbreeding, and reduction in gene flow.

12. GENETIC DRIFT
• variation in the relative frequency of different
genotypes in a small population, owing to the
chance disappearance of particular genes as
individuals die or do not reproduce.
• Loss of genetic variation
• Random process
• Useful alleles for fitness can be lost

13. INBREEDING
• mating between closely related individuals
• Greater in small population
• Increases proportion of homozygotes
• Inbreeding Coefficient (F) – measures the probability that
two alleles of a given gene are derived from a common
ancestral allele.
Declining population = decreasing
heterozygous in each generation

14. • Self-pollinating plants – high levels of homozygosity
and relatively little genetic variation within single
populations (except different).
• Outbreeding species - inbreeding results reduced
fitness and lower survival rates among offspring.
• Inbreeding Depression – increased homozygosity for
deleterious alleles.
• Genetic load (or genetic burden) – # of deleterious
alleles present in the gene pool of a population

15. REDUCTION IN GENE FLOW
• Migration– main route for gene flow (exchange of
alleles between populations) in animals
• Cross-pollination/ seed dispersal – plants
Isolation and population fragmentation in rare and
declining species significantly reduce gene flow
HINDRANCES?

16. GENETIC EROSION THREATENS
SPECIES’ SURVIVAL
• Genetic erosion – The loss of previously existing
genetic diversity from a population or species.
• Two important effects on a population:
2. Reduction in levels of heterozygosity.
1. it can result in the loss of potentially useful alleles from
the gene pool, thus reducing the ability of the
population to adapt to changing environmental
conditions and increasing its risk of extinction.

17. Conservation of Genetic Diversity
Is Essential to Species Survival
EX SITU CONSERVATION
• Captive –breeding programs
• Gene banks
IN SITU CONSERVATION
• Establishment of parks and reserves
POPULATION AUGMENTATION

18. EX SITU CONSERVATION
• Ex situ (Latin for off-site) conservation
involves removing plants or animals
from their original habitat to an
artificially maintained location such as a
zoo or botanic garden.
• Ex. Captive Breeding

19. EX SITU CONSERVATION
• Gene banks – preservation for reproductive components,
such as sperm, ova, and frozen embryos in the case of
animals, and seeds, pollen, and cultured tissue in the case of
plants.
• Disadvantage: large collections cannot contain all the genetic
variation that is present in a species.
• Solution: Core collection – is a subset of individual genotypes,
carefully chosen to contain as much as possible of the species’
genetic variation;

20. EX SITU CONSERVATION
greatest biological diversity in both domesticated and
non domesticated species is frequently found in
underdeveloped countries, most ex situ collections
are situated in developed countries that have the
resources to establish and maintain them.

21. IN SITU CONSERVATION
• In situ (Latin for on-site)
conservation – preserve the
population size and
biological diversity of a
species while it remains in
its original habitat.

22. POPULATION AUGMENTATION
• Population augmentation—boosting the numbers of a
declining population by transplanting and releasing
individuals of the same species captured or collected
from more numerous populations elsewhere.

23. • Genetic swamping – gene pool of the original
population is overwhelmed by different genotypes
from the transplanted individuals and loses its identity.
• Outbreeding depression – reduced fitness occurs in
the progeny of matings between genetically diverse
individuals.
POPULATION AUGMENTATION RISKS

24. Outbreeding depression that occurs in the F2 and later
generations is due to the disruption of
Coadapted gene complexes—
groups of alleles that have evolved to work together
to produce the best level of fitness in an individual.
POPULATION AUGMENTATION RISK

25. Conservation genetics uses a combination of ecology,
molecular biology, population genetics, mathematical
modeling, and evolutionary taxonomy. It is both a basic
and an applied science. A community rather than
individual effort. First, scientists must understand the
genetic relationships among the organisms they're
studying. Then wildlife managers use techniques to
preserve biological diversity in these species.
SUMMARY