Genetic drift is a random change in the frequency of genes (alleles) in a plant population over time. It happens by chance, not because of natural selection.
How it occurs:
- Small population size:
Genetic drift has a stronger effect in small plant populations. If only a few plants reproduce, some alleles may be passed on more often just by luck, while others may disappear completely. - Random events:
Events like droughts, floods, fires, or human activities can randomly kill some plants, leaving a smaller population with different gene frequencies than before. - Founder effect:
When a few plants from a large population start a new colony in a new area, the new group may not carry all the genetic variation of the original population. This can change allele frequencies. - Bottleneck effect:
When a population is drastically reduced in size due to an environmental event, only a few individuals survive. Their genes dominate the next generations, reducing overall genetic diversity.
Effects of genetic drift:
- Loss of genetic variation: Some alleles may disappear completely.
- Increased genetic difference: Different populations of the same species may become genetically distinct over time.
- Reduced adaptability: With fewer alleles, the population may struggle to adapt to new environmental changes.
In short:
Genetic drift is the random change in gene frequencies in a plant population, often stronger in small populations. It can reduce genetic diversity and affect how plants evolve over generations.