1. Conservation Genetics
Why should we be concerned with genetic diversity when more severe threats threaten entire systems?
First, the rate of evolutionary change in a population is proportional to the amount of genetic diversity available
Fundamental Theorem of Natural Selection

2. Conservation Genetics
Second, diversity as measured at the level of genes or quantitative genetic traits represents the primary level of biodiversity
Every biochemical product, every growth pattern, every instinctive behavior, every color morph is encoded in the in the ‘genetic library’ of each species

3. Conservation Genetics
Third, there are many conservation challenges that benefit from the guidance and direction that genetic data, collected and interpreted with the constructs of sound population genetic theory, can furnish

4. Conservation Genetics
The basic link from genetics to conservation is that of small populations, which tend to lose genetic diversity over time
The power of conservation genetics comes in the form of tools which allow one to identify unique evolutionary lineages, monitor dispersal movements, estimate population size, or trace genetic changes through time

5. Conservation Genetics
In this chapter we will go over the principles of genetics and how they may aid in conservation
Next, we will provide a board overview of contemporary efforts and controversies in conservation genetics

6. Conservation Genetics

7. Genetic Variation
A species’ pool of genetic diversity exists on 3 levels: variation within an individual, differences among individuals w/in a pop(n), differences among popuations

8. Conservation Genetics

9. Conservation Genetics variation w/in the individual
Chromosomes consist of long sequences of nucleotides, some of which code for molecules that create the structure and the physiological functions of an organism
A gene represents a specific segment of DNA of a specific chromosome pair that (1) codes for the primary structure of proteins

10. Conservation Genetics variation w/in the individual
(2) codes for the formation of ribonucleic acid (RNA), or (3) regulates the location and time of gene expression
The majority of genetic material does not code for any product (thus not subject to NS, unless linked)
This is termed neutral genetic variation and is frequently analyzed when examining evolution change…problem?

11. Conservation Genetics variation w/in the individual
One such problem is you may be asking questions pertaining to adaptive variation (i.e. genes under selection)
So while we are very concerned with maintaining the adaptive variation, we usually don’t know where in the genome that exists (see Box 11.1)

12. Conservation Genetics variation w/in the individual
A physical or behavioral character (phenotype) can be expressed directly as a trait may be entirely due to genotype (e.g. eye color) or environment (nutritional regime), but more likely a combination of both (e.g. skin color)
Quantitative genetics are helpful in determining how much of the phenotype is attributable to genes (Box 11.1)

13. Conservation Genetics variation w/in the individual
The ultimate source of variation is mutation
Mutations range from a change in a single base, deletion or duplication of a group of nucleotides, to large-scale changes such as deletion, duplication, or translocation of large parts of the chromosome (or the entire chromosome)
Are they good, bad, or ugly?

14. Conservation Genetics variation w/in the individual
Recombination is another source of variation, requires sexual recombination
At the population level, a given locus is either monomorphic (both copies always found without variation) or polymorphic (two or more types of the alleles possible)
The overall level of heterozygosity (the proportion loci in an individual that contains alternative)

15. Conservation Genetics variation w/in the individual
What is the value of focusing on genetic variation within individuals?
First, heritable genetic variation is the basis for evolutionary change and the individual is where NS operates
Second, the individual is where problems associated with inbreeding occur

16. Conservation Genetics variation w/in the individual
Third, knowledge of individual genotypes may be important in some captive breeding programs
Finally, genetic variation is always measured in individuals and can only be estimated for collections (i.e. populations) through statistical summaries

17. Conservation Genetics variation among individuals
Variation among individuals, or pop-level variation, consists of the types of alleles present and their relative frequencies across all members of a population considered together (the gene pool)

18. Conservation Genetics variation among individuals
Which has the highest mean Hp? Why are other populations (e.g. Litchfield) so low?

19. Conservation Genetics variation among individuals
Are gene frequencies constant?
They frequently change over time due to mutation, NS, and random processes such as genetic drift, non-random mating, small pop size, and I & E (gene flow)

20. Conservation Genetics variation among individuals
There have been a number of attempts to link ecological characteristics ad levels of genetic variation
Not surprisingly, widespread organisms tend to have higher levels of genetic diversity while small range, small populations or large body size are correlated with low diversity (see Table 11.3)

21. Conservation Genetics variation among individuals

22. Conservation Genetics variation among populations
Species rarely exist as single, randomly interbreeding, or panmictic populations spread across large areas (or there is structure within and among populations)

23. Conservation Genetics variation among populations
Diversity is variable, but also higher than any individual site

24. Conservation Genetics variation among populations
Thus, genetic diversity among a set of populations consists of within-population diversity and among-population divergence
Thus a simple genetic diversity model is: where HT = total genetic variation, HP= average diversity within pop(n), and DPT = average divergence among pop(n)
HT = HP + DPT

25. Conservation Genetics variation among populations
Divergence may result from a number of processes including random processes (e.g. founder effects, genetic drift, episodic population bottlenecks) and from local selection
Again, important to remember we can quantify within and among-population diversity components

26. Conservation Genetics variation among populations
RCWO has mean heterozygosity of 7.8% which is typical
Of total variation, 14% consists of among- and 86% consists of within pop(n)
The among is higher than most species, which tend to be more site-specific than many other sp

27. Conservation Genetics variation among populations
Ecological correlates can subsequently influence genetic structure by influencing movement
E.g. white-tail deer vs. Alpine Ibex

28. Conservation Genetics variation among populations
One frequent question is if current mortality rates are negatively impacting the health of the population (use previous approach)
The type of genetic marker has issues: molecular markers are usually neutral but are used as a proxy for adaptive variation…(because gene not known)
Adaptive divergence may not be the same as adaptive variation

29. Conservation Genetics variation at the metapopulation
We have utilized the metapopulation paradigm to describe populations on a fragmented landscape
By definition, metapopulations interact, thus influencing the genetic structure of the populations
Metapopulations lose genetic variation more rapidly than a single large pop(n)

30. Why is Genetic Diversity Important?
The amount of adaptive variation in a population should be related to the health of a population, or to its ability to withstand stresses and challenges
There have been a number of general correlates of genetic variation among populations (Table 11.5)

31. Why is Genetic Diversity Important?

32. Why is Genetic Diversity Important?
There is mixed results on the actual importance of adaptive genetic diversity
There is no absolute value of heterozygosity that indicates a population’s health, although it may be correlated with individual fitness (taxonomic comparisons see Table 11.4)

33. Why is Genetic Diversity Important?
However, while the absolute level of heterozygosity may not provide a clear level of risk, loss of it does indicate serious problems
E.g. low RS following inbreeding is usually accompanied by low HP
There is some evidence
E.g. Drosophila and inc. salinity & HP

34. Why is Genetic Diversity Important?
Among-population divergence may play a critical role in local fitness and population survival
First, pop(s) may be locally adapted (?)
Second, coadapted gene complexes may arise in local pop(s) (Essay 11.1)

35. Forces that Affect Genetic Variation w/in Pop(s)
When making predictions about likely changes in allele frequency, not the difference between N and Ne (effective populatiton size)
Ideal is large, panmictic, 1:1 sex ratio

36. Forces that Affect Genetic Variation w/in Pop(s)
Mutations are the ultimate source of new genetic variation with mutations being rare and most being neutral
This is generally not a problem until popo(s) become small…why?
The gradual accumulation of deleterious mutations results in the mutational meltdown (mean viability lowered, and pop(s) become smaller, with fixation)

37. Forces that Affect Genetic Variation w/in Pop(s)
Genetic drift is the random fluctuation of gene frequencies over time due to chance alone
Because of sexual mating (and only one copy being passed on) there is a high chance that not all alleles will not be passed on
Drift can occur very quickly in small pop(s)

38. Forces that Affect Genetic Variation w/in Pop(s)
Average % of genetic variance remains over 10 generation in a theoretical, idealized pop(n) at various genetically effective pop(n) size Ne

39. Forces that Affect Genetic Variation w/in Pop(s)
Ultimately, in any small pop(n) is genetic drift will result in the fixation of one allele at 100%
The likelihood of that occurring is equal to the initial allele frequency (e.g. 0.8)

40. Forces that Affect Genetic Variation w/in Pop(s)
When a demographic bottleneck occurs, the magnitude of the genetic loss depends not only on the size of the bottleneck but also on the growth rate of the population afterward

41. Forces that Affect Genetic Variation w/in Pop(s)
Recovery is quickest when pop(s) have a high growth rate (r) and when bottleneck is less severe

42. Forces that Affect Genetic Variation w/in Pop(s)
Rare alleles are lost from small, isolated populations

43. Forces that Affect Genetic Variation w/in Pop(s)
Gene flow is the movement of genes from one population to another
Measuring gene flow is problematic
Not all breed
Cannot account for historical dispersal
Similarity could be recent ancestor

44. Forces that Affect Genetic Variation w/in Pop(s)
Inbreeding can lead to decreased fitness (inbreeding depression) either by the expression of deleterious recessive alleles or the loss of heterozygosity

45. Forces that Affect Genetic Variation w/in Pop(s)
Data from domestic animals indicate a 10% increase in inbreeding coefficient will result in a 5-10% decline in ind RS

46. Forces that Affect Genetic Variation w/in Pop(s)
Lab studies of land snails and white-footed mice were inbred and outbred and released…
Results of WFM

47. Forces that Affect Genetic Variation w/in Pop(s)
Not all low levels of heterozygosity or even inbreeding should be alarming
Some natural populations have apparently experienced low levels of inbreeding for several generation with little to no harm

48. Forces that Affect Genetic Variation w/in Pop(s)
Outbreeding depression can

49. Forces that Affect Genetic Variation w/in Pop(s)

50. Forces that Affect Genetic Variation w/in Pop(s)

51. Forces that Affect Genetic Variation w/in Pop(s)

52. Forces that Affect Genetic Variation w/in Pop(s)

53. Why is Genetic Diversity Important?

54. Why is Genetic Diversity Important?

55. Conservation Genetics variation at the metapopulation