Genetic insights into the African Yam Bean (Sphenostylis stenocarpa, (Hochstex. A. Rich.) Harms) revealed through the ribulose-1,5-bisphosphate carboxylase/oxygenase large (rbcL) gene

Abstract

In the present study, the genetic diversity of 47 AYB leaf samples from various regions in Nigeria was evaluated using the rbcL gene marker. Phylogenetic analysis classified the samples into two main groups. Principal coordinate analysis (PCoA) did not show clear clustering. The Linear Genetic Distances (LGD) between the gene sequences varied from 3.60551 to 9.797959, indicating significant genetic diversity. Analysis of molecular variance (AMOVA) revealed that 99% of the genetic variation was within populations. Of the 66 rbcL gene sites examined, 54 were polymorphic, resulting in 45 haplotypes with a haplotype diversity of 0.998 ± 0.005 and a nucleotide diversity of 0.22741 ± 0.0003. A total of 118 single-nucleotide polymorphisms (SNPs) were identified in the rbcL gene of African yam bean (AYB). Among these, 105 mutations (89%) were nonsynonymous, indicating functional genetic variation, while 13 mutations (11%) were synonymous. The transversion-to-transition mutation ratio was 74:44, corresponding to 63% and 37%, respectively. These results underscore the need for more focused breeding initiatives to maximize AYB’s agricultural and nutritional benefits.