Assessment of genetic diversity of indigenous chicken ecotypes in selected areas of Tanzania
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Date
2024
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Sokoine University of Agriculture
Abstract
Indigenous chickens are raised in a free-range and scavenging system.
However, an increased loss of diversity has been observed, and the
indigenous chicken genetic resources are considered to be the most
threatened due to the uncontrolled distribution of exotic breeds and
selective breeding by farmers. The purpose of this study was to assess
the diversity of indigenous chickens according to their phenotypic
characteristics based on their qualitative and quantitative characteristics
and genotype characteristics based on their allelic profiles in Bahi
Dodoma and Songea Ruvuma Tanzania for conservation purposes and
sustainable use. This was established by first determining the sample of
one hundred (100) chickens using a random sampling technique.
Phenotypic characteristics were then analyzed qualitatively and
quantitatively, and 1 ml of blood was drawn from the chicken wing vein
to assess genotypic characteristics using microsatellite markers. Data
from the qualitative and quantitative analysis were analyzed by using
Statistical Package for Social Sciences (SPSS) version 16.0 and Origin
Pro. Version 2019. P-value < 0.05 was used as a cut-off point for
statistical significance. GenAIEX v.6.5 software was used to analyze
genetic diversity parameters. For the case of phenotypic characteristics,
there is no significant difference in body weight and chest circumference
between the chicken from Bahi and Songea at p < 0.05, for the case of
body length, wingspan and shank length there is statistical significance
between Bahi and Songea chicken at p < 0.05. Shank colours were
associated with plumage colour, chickens with black plumage had black
shanks, while white plumage chickens exhibited the same pattern, and
single comb type was identified as the dominant one in this study for
62% Bahi and 88% Songea. Genetic diversity revealed that Bahi had a
total of 117 alleles while Songea had 111 alleles averaging 6.5 and 6.1
per locus for Bahi and Songea, respectively. The locus with the least
number of alleles was MCW0078, with just 5 alleles, whereas the MCW0111F locus was highly polymorphic with 20 alleles. The mean
number of different alleles (Na) was 7.250 ± 0.544 for Bahi and 7.000 ±
0.742 for Songea, with an overall average of 7.125 ± 0.515. The
number of private alleles was 31 and 37 for Bahi and Songea,
respectively. Genetic variation among the population was found to be
17%, while within the population, it was 83%. Nei’s genetic distance
was calculated to be 0.589, and the principle of coordinate analysis
revealed two clusters with some intermixes. This study showed a
significant phenotypic variation and relatedness between the two
chicken ecotypes, likely influenced by an individual’s genetic makeup
hence, they are very useful in conservation programs and sustainable
use of the indigenous chickens.
Description
Dissertation
Keywords
Genetic diversity, Indigenous chicken, Microsatellite marker, Bahi district, Songea district, Social Sciences (SPSS) version 16.0