Genetic Diversity, Habitat Fragmentation and Epigenetic Variations

Abstract

There is an increase in the levels in which tropical rainforest and temperate grasslands have become anthropogenically fragmented in recent years. However, an understanding of the genetic and epigenetic mechanisms coupled with conservation biology and biodiversity studies is crucial in explaining habitat fragmentation implications in stable ecosystems (Fahrig, 2003; Henle et al., 2004). The utilization of genetic variability and adaptability can be used as a stepping stone in identifying germplasms that can be used in the search of new ecotypes with novel genes which can be incorporated in crop, fodder and cover tree improvement programs in other similar reclaimable ecological zones. Studies have shown that there is a considerable genetic variability within or between natural populations. This variability provides a genomic flexibility that can be used as a raw material for plant adaptation as pioneer species. There is need to seek for higher genetic variability so as to increase the capacity of an organism to adapt to the ever changing environmental conditions (Ellstrand and Elam, 1993). Low genetic variability has been associated with the inability to cope with abiotic and biotic stresses (Valen, 1965). It is now possible to compare and analyze the pattern and spectrum of genetic variations within or between using molecular genetic tools (Zhang et al., 2009, Madan et al., 2002; Reisch et al., 2005). The amplified fragment length polymorphism (AFLP) is one of the most precise, cost effective polymerase chain reaction (PCR) based ecological tool that has been used for molecular analysis of such population genetic diversity analysis (Vos et al., 1995; Bensch, and Akesson, 2005). It has been shown to be comparatively highly informative, reliable and efficient tool in other grass investigations (Fjellheim and Rognli, 2005). Such tools can be used to determine the correlation between the genetic differentiation and geographic distance among different populations. However, the level of genetic differentiation can be affected by more than one ecological factor in a geographical region, especially environmental heterogeneity (Liu et al., 2004). Other factors could be natural mutation, artificial selection, and combined ecological factors which are instrumental in the differentiation into ecotypes (Liu et al., 2002). Therefore, variations in gene expressions which are caused by abiotic and biotic stresses in the environment trigger epigenetic mechanisms like cytosine DNA methylation which have