Tracing Worldwide Turkey Genetic Diversity Using D-loop Sequence Mitochondrial DNA Analysis

Abstract

Simple SummaryThe development of new production lines of turkeys has relegated native breeds to a second position. This has increased the need for new research to ensure the conservation of local turkey breeds and the maintenance of biodiversity. The objective of the present study was to identify turkey populations, their origins, and maternal lines through mitochondrial DNA analysis. For this study, mitochondrial DNA samples from 93 turkeys (Meleagris gallopavo) were used. The animals belonged to populations in Brazil, Mexico, Spain (Andalusia and Majorca) Italy, Iran, Egypt, and the United States. The haplogroup network that formed suggested that turkey domestic populations group into a single haplotype. However, genetic differences within the haplogroup were found. The present study may provide a better approach for the implementation of conservation strategies for domestic turkey populations.AbstractAccording to recent archeological evidence, turkey (Meleagris gallopavo gallopavo) domestication may have occurred in Mexico around 2000 years ago. However, little is known about the phylogenetic and genealogical background underlying domestic turkey populations. This study aimed to further understand the domestication process and identify inter- or intraspecific connections between turkey populations to determine their origins, trace their global expansion, and define the species’ genetic value. Ninety-three domestic turkeys (local breeds) were sampled from populations in Brazil, Mexico, USA, Spain, Italy, Iran, and Egypt. Publicly available sequences from previous studies were also included. Standard mitochondrial DNA, genetic diversity, and haplotype network analyses were performed. Seventy-six polymorphic sites were identified. Turkeys from Mexico showed the greatest number of polymorphic sites (40), while turkeys from Italy and Brazil reported only one site each. Nucleotide diversity was also highest in Mexico and the USA (π = 0.0175 and 0.0102, respectively) and lowest in Brazil and Italy. Of the six major haplogroups defined, the Mexican and USA populations appeared to have remained more stable and diverse than the other populations. This may be due to conservative husbandry policies in the rural areas of other populations, which have prevented the introduction of commercial turkey lines.

Copy Number Variants in Four Italian Turkey Breeds

“…The genetic variability in turkey populations has been recently studied mainly using Single Nucleotide Polymorphisms (SNPs) as markers [ 12 , 13 , 14 , 15 ] and by the analysis of mtDNA D-loop sequences [ 16 ]. Copy number variants (CNVs) in turkeys species are still poorly studied [ 17 , 18 , 19 ].…”

Genetic Diversity and Identification of Homozygosity-Rich Genomic Regions in Seven Italian Heritage Turkey (Meleagris gallopavo) Breeds

“…This occurred either where genomic selection (e.g., bovine breeds) has been adopted or in small and endangered populations where in situ genetic conservation plans are desired. Heritage turkey breeds were recently studied and, even if still limited, some indication about their genomic variability and diversity is nowadays available [ 4 , 5 , 6 , 7 , 8 , 9 ]. Recent studies were performed on run of homozygosity (ROH): Marras et al characterized ROH-rich regions in a commercial turkey hybrid, and Strillacci et al discussed the difference in ROH between the autochthonous Mexican and commercial hybrid turkeys [ 10 , 11 ].…”

Hybrid Versus Autochthonous Turkey Populations: Homozygous Genomic Regions Occurrences Due to Artificial and Natural Selection

“…Genomic research in turkeys quickly developed in the last years thanks to the availability of a reference genome [ 6 ] and individual sequences, which opened opportunities also in whole-genome SNP discovery. Studies characterizing the genetic/genomic variability of turkey populations using SNPs markers (including mtDNA) are still limited [ 7 , 8 , 9 , 10 , 11 ]. Among these studies, Marras et al [ 8 ] analyzed for the first time runs of homozygosity (ROH) in commercial turkey hybrids but no study is available, at best of our knowledge, on any autochthonous turkey population not under such strong artificial selection.…”