Analysis of the genome of one of world’s ‘big three’ food
crops provides clues to better breeding, higher yield
Bread wheat (Triticum aestivum) is one of the “big three” globally
important crops, accounting for 20% of the calories consumed by people. Fully
35% of the world’s 7 billion people depend on this staple crop for survival.
Now an international team of scientists, including a group from Cold Spring
Harbor Laboratory (CSHL), has completed the first comprehensive analysis of its
full genome.
The study reveals the evolution of bread wheat from
ancestral strains through to its current domesticated form. Due to the
complexity of the plant’s genome the analysis proved a technically
challenging. But the potential payoff is
large: developing new strategies for breeding and improving wheat crops.
A complex technical
challenge
To put the huge size of the bread wheat genome into context,
its constituent number of paired DNA bases, or nucleotides, totals
17,000,000,000 base-pairs (17 Gb). This
is about five times the amount of DNA in the human genome. However, as much as
80% of the bread wheat genome consists of repetitive sequences. Because of the
way genomes are usually sequenced – by stitching together hundreds of millions
or billions of tiny fractions of a full genome -- the bread wheat genome’s size
makes it very hard to determine which part of the genome any particular
sequence readout has come from, and whether it is a unique or repeat sequence.