Conclusions and Discussion - Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry - page 308

18

CHAPTER

Conclusions and Discussion

This chapter is divided into two parts: conclusions derived earlier in the
book, followed by a discussion of the relevance of NEWGARDEN analyses
for evolutionary theory and conservation practices.

Conclusions

Below is a summary of some of the conclusions drawn from NEWGARDEN
analyses presented in previous chapters concerning ways in which
differences in spationumerical patterns of founders can affect population
growth and genetic diversity retention.
The conclusions are listed roughly in the order that they appear in the
book.
NEWGARDEN can be used to explore differences in population
growth rates, changes in heterozygosity, unique allele preservation, and
F values in comparative newly establishing or bottlenecked populations
with different allelic arrays, different patterns of spatial establishment
for the same number of founders or survivors, and different life history
characteristics (e.g., degree of selfi ng, dispersal distance characteristics,
age-specifi c mortality).
Retention of unique alleles is often a more sensitive measure of the
preservation of genetic diversity than heterozygosity in such NEWGARDEN
trials. As the number of alleles per locus or the number of low frequency
unique alleles increases, the degree to which unique alleles are retained
increases in relevance as a measure of genetic diversity maintenance
compared to heterozygosity.
Unique allele loss can be more rapid when there are numerous lower
frequency unique alleles at a locus than when there are the same number of
such unique alleles, but with only one low frequency unique allele at each
of several loci. Increasing the number of different low-frequency alleles per
locus decreases the probability of capturing all unique alleles in populations
that establish from a smaller number of founders.
If one is interested in using NEWGARDEN to examine the effects of
changing various life history input characteristics, founder number and
placement geometry should be held constant.