SNPs, SSRs and inferences on cassava's origin

Area of Science:

• Genetics
• Plant Science
• Agricultural Research

Background:

• Cassava (Manihot esculenta ssp. esculenta) is a crucial tropical staple food, yet its origins remained unclear.
• Previous research has not extensively focused on the evolutionary history of this important crop.

Purpose of the Study:

• To trace the evolutionary and geographical origins of domesticated cassava.
• To investigate the genetic diversity within cassava and its wild relatives.

Main Methods:

• Analysis of single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) variation.
• Examination of genetic diversity in 20 cassava varieties and 212 individuals from wild Manihot species.
• Sequencing of nuclear genes (BglA, Hnl, G3pdh) and analysis of SSR loci.

Main Results:

• Shared SNPs and SSR alleles were found between domesticated cassava and a specific wild Manihot population.
• Evidence suggests cassava was domesticated from a single species, Manihot esculenta ssp. flabellifolia.
• The southern Amazon basin is identified as the most probable origin for cassava.

Conclusions:

• Cassava's domestication involved a single wild progenitor, challenging previous hybridization theories.
• The origin of cassava is pinpointed to the southern Amazon basin, providing critical insights into its history.
• This study enhances our understanding of cassava's genetic background and domestication process.