Species and Phenotypic Distribution Models Reveal Population Differentiation in Ethiopian Indigenous Chickens.

Fasil Getachew Kebede,Setegn Worku Alemu,Tadelle Dessie,Hans Komen,Olivier Hanotte,John W M Bastiaansen

doi:10.3389/fgene.2021.723360

Fasil Getachew Kebede, Setegn Worku Alemu + Show 4 more

Open Access

https://doi.org/10.3389/fgene.2021.723360

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Abstract

Smallholder poultry production dominated by indigenous chickens is an important source of livelihoods for most rural households in Ethiopia. The long history of domestication and the presence of diverse agroecologies in Ethiopia create unique opportunities to study the effect of environmental selective pressures. Species distribution models (SDMs) and Phenotypic distribution models (PDMs) can be applied to investigate the relationship between environmental variation and phenotypic differentiation in wild animals and domestic populations. In the present study we used SDMs and PDMs to detect environmental variables related with habitat suitability and phenotypic differentiation among nondescript Ethiopian indigenous chicken populations. 34 environmental variables (climatic, soil, and vegetation) and 19 quantitative traits were analyzed for 513 adult chickens from 26 populations. To have high variation in the dataset for phenotypic and ecological parameters, animals were sampled from four spatial gradients (each represented by six to seven populations), located in different climatic zones and geographies. Three different ecotypes are proposed based on correlation test between habitat suitability maps and phenotypic clustering of sample populations. These specific ecotypes show phenotypic differentiation, likely in response to environmental selective pressures. Nine environmental variables with the highest contribution to habitat suitability are identified. The relationship between quantitative traits and a few of the environmental variables associated with habitat suitability is non-linear. Our results highlight the benefits of integrating species and phenotypic distribution modeling approaches in characterization of livestock populations, delineation of suitable habitats for specific breeds, and understanding of the relationship between ecological variables and quantitative traits, and underlying evolutionary processes.

Highlights

Smallholder farmers in Africa keep scavenging poultry as a source of affordable animal protein and a means of income
Before classifying the 26 sample chicken populations into ecotypes through hierarchical clustering based on similarity for quantitative traits, we reduced the number of traits through discriminant analysis (Table 1)
Sustainable livestock production in the tropics requires adaptive genotypes which can withstand the undesirable effects of climate change and produce optimally (Fleming et al, 2017; Bettridge et al, 2018)

Summary

Introduction

Smallholder farmers in Africa keep scavenging poultry as a source of affordable animal protein and a means of income. A starting point in genetic improvement of the existing local chicken populations or in considering the introduction of new genotypes is to understand how the environment is driving local adaptation (Bettridge et al, 2018). This knowledge would allow breeding of indigenous ecotypes that are more productive under village conditions while retaining locally acceptable morphological and adaptive traits (Dana et al, 2010; Muchadeyi and Dzomba, 2017; Birhanu et al, 2021)

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