Animal Molecular Breeding 2016, Vol.6, No.3, 1-5
3
biological diversity lead to changes in the environment, leading to adaptation of the remaining species; and
changes in genetic diversity leads to a loss of biological diversity (Pullin, 2002). As breeds continue to undergo
diversity and variation, most of the desirable genetic materials are lost. Conservation principles help to preserve
the genetic constituent of species which are necessary for species to evolve. Species that have less genetic
variation are at a greater risk.
4 Measuring Genetic Diversity
The maintenance of genetic diversity of poultry resources at adequate levels require systematic scientific
application of conservation biology principles. This entails the integration of population genetics and molecular
biology.
Breeds in many cases have been described based on a few phenotypic traits, not minding that large parts of the
genomic make-up of these breeds might be in common. To set up efficient conservation measures, therefore,
reliable information about genetic difference between individuals, populations and breeds are required. In the
differentiation of poultry breeds emphasis have been shifted from morphological and feather coloring
characteristics to differentiation based on measurements at the molecular level (Pym, 2013). Weigend et al. (2013)
enumerated the major forces creating genetic differences between breeds and populations to include mutation and
recombination, genetic drift, natural selection and migration.
5 Phenotypic Approach to Measurement of Genetic Diversity
5.1 Using phenotypic markers
This gives an initial insight into breed diversity by examining the differences in phenotypic traits. Phenotypic
markers may be subdivided into discrete traits (such as morphological characters and phenes) and continuous
traits (like body measurements) that are applicable to assessing genetic variation and phylogenetic relationships
between various breeds and populations. Several authors have used this approach to differentiate breeds of
animals (Ebegbulem et al.
,
2011; Salako and Ngere, 2002; Moiseyeva et al., 1994; Nikiforov et al.,
1998).
5.2 Using biochemical markers
Application of protein polymorphisms and physiological traits in the estimation of genetic variation within and
between poultry (and other animals) populations have been reported by several authors (Ukwu and Ibe, 2012;
Nosike et al., 2013; Oke et al., 2012 ; Romanov, 1994).
5.3 Using immunogenetic markers
Such as blood groups, is another class of polymorphic markers. They are characterized by genotyping
complications and require an accurate locus and allele identification (Weigend et al., 2013).
6 Measuring Genetic Diversity Using Molecular Markers
The assessment of genetic variability at the DNA level has been enabled by the recent advances in molecular
technology. Different classes of molecular markers such as restriction fragment length polymorphism (RFLP),
endogenous avian virus loci, random amplified polymorphic DNA (RAPD) markers, amplified fragment length
polymorphisms (AFLP), mitochondrial DNA (mtDNA) markers, microsatellites and minisatellites, as well as
single nucleotide polymorphisms(SNP) markers have been used in genetic diversity studies (Weigend et al.,
2013
)
.
According to Weigend and Romanov (2001) the assessment of DNA marker polymorphism suggests that
variability in DNA is a powerful tool for examining diversity within and among individuals, families and
populations. The authors added that the major advantages of these highly polymorphic markers are their locus
specificity, abundance and random distribution over the genome , and their co-dominant inheritance.
Studies have shown that microsatellite typing can be applied to pooled DNA samples for population studies
(Semik and Krawczyk, 2011; Hillel et al.,
2003). The biodiversity of 52 chicken populations was evaluated (Hillel
