Mitochondrial DNA D-loop sequence variation among 5 maternal lines of the Zemaitukai horse breed

Genetic variation in Zemaitukai horses was investigated using mitochondrial DNA (mtDNA) sequencing. The study was performed on 421 bp of the mitochondrial DNA control region, which is known to be more variable than other sections of the mitochondrial genome. Samples from each of the remaining maternal family lines of Zemaitukai horses and three random samples for other Lithuanian (Lithuanian Heavy Draught, Zemaitukai large type) and ten European horse breeds were sequenced. Five distinct haplotypes were obtained for the five Zemaitukai maternal families supporting the pedigree data. The minimal difference between two different sequence haplotypes was 6 and the maximal 11 nucleotides in Zemaitukai horse breed. A total of 20 nucleotide differences compared to the reference sequence were found in Lithuanian horse breeds. Genetic cluster analysis did not shown any clear pattern of relationship among breeds of different type

Variation in the mitochondrial control region sequence between the two maternal lines of the Sorraia horse breed

The mitochondrial control region sequence was compared between the two surviving matrilineal lineages of the Sorraia horse. Two haplotypes were found, showing three differences between them. The reduced number of surviving maternal lineages emphasizes the importance of establishing a conservation plan for this endangered breed

Insights into the genetic structure of the cowpea pest Callosobruchus maculatus in Africa

The bean beetle Callosobruchus maculatus is a worldwide generalist legume seed pest, present in the tropics and subtropics. Despite its economic importance, little is known about the population structure and migration patterns of this bruchid beetle in its continent of origin, both at local and regional scales. Gaining knowledge in the demographic processes experienced by C. maculatus, in particular in its native area, might give clues to understand evolutionary forces that have driven its expansion in traditional agroecosystems. Here, we analyze the genetic structure of 23 African populations of C. maculatus located in eleven different countries, using nuclear (28S) and mitochondrial (CytB) markers, and further apply phylogenetic and demographic analyses. The 28S sequences showed low genetic variability. In contrast, the analysis of CytB indicated significant genetic differentiation between most populations, suggesting low levels of gene flow, even at a reduced spatial scale. The results obtained from the estimation of various demographic parameters suggest evidence of recent population expansion, in agreement with a scenario of long-distance dispersal through trade of legume seeds for human consumption and population growth related to its pest nature. Overall, our results show that biogeography, isolation processes and human-mediated dispersal events drive the genetic structure of this pest in Africa