Genetic integrity: a key aim

Maintaining the genetic integrity of accessions is one of the cornerstones of genetic resources conservation. Every population of seeds has a shared genetic profile. Assuming this genetic profile has not been interfered with, individual seeds within that population are said to have genetic integrity. The genes they carry are as close as possible to those in the original sample, and distinct from the genotypes of other accessions.

Genetic integrity can be at risk at all stages of processing by genebanks, so genebanks must put careful handling procedures in place, in order to avoid the inadvertent introduction of new genes into the population. In order for a genebank to support agricultural research and global food security, it is important to share exactly the same germplasm as the original collected material.

Genetic integrity is threatened by mislabeling, pollen contamination, seed contamination, or unintended selection over many cycles of regeneration. It can also be threatened if the viability of seeds drops so low that only a limited number of seeds are left, resulting in a reduction of genetic variation within the sample.

One natural process that can threaten genetic integrity is genetic drift. Genetic drift is the change in frequency of an existing gene variant in a population, due to random chance. Genetic drift may cause gene variants to disappear completely, and thereby reduce genetic variation. It may also cause initially rare gene variants (alleles) to become much more frequent. Genetic drift can be beneficial in nature - it drives evolution - but in genebanks it must be avoided at all cost, since it can lead to loss of genetic integrity.