Every cell in humans has two different versions of the same gene. Each child is given one allele by their parents. The genes are linked on the chromosomes. This is sometimes not the case. What's the reason?
Recombination is a process that shuffles the allle content between the chromosomes. The exchange of genetic material occurs when the chromosomes of the same sex contact each other.
The potential of increasing genetic diversity and assembling desired combinations of all genes has fascinated scientists for a long time. The "Goldilocks principle" is that at least one is required for successful sexual reproduction and a lack of it is a major cause of Down Syndrome.
It's not uncommon for the number to not exceed three. It is possible to achieve a limit on the number of crosses by using the phenomenon of interference. How this interference works has been a mystery since it was first described.
A new model of interferences.
A team led by Raphael Mercier at the Max Planck Institute for Plant Breeding Research in Cologne, Germany, have found convincing evidence in support of a recently proposed model.
The work spearheaded by Stéphanie Durand and her team, along with other people, achieved these insights by manipulating the expression of certain genes in a model plant.
The expression of the pro-crossover proteins HEI10 was boosted and the expression of the ZYP1 was disrupted.
When the scientists combined the two interventions, they were surprised to see a huge increase in crossovers. It barely affected cell division.
There is an emerging model for how the number is regulated. The model was formulated by the team at the Max Planck Institute for Dynamics and Self-Organization in Gttingen, Germany.
HEI10 forms multiple small foci and is consolidated into a small number of large foci. The model suggests that the formation of droplets along an axis appears to be the key to the success of the model.
The team's findings are an exciting insight into a process that has puzzled scientists for over a century. We want to understand the dynamics of the HEI10 droplets. If we can get a better handle on how the process works, we may be able to boost recombination during plant breeding, allowing the assembly of combinations of beneficial alleles that have remained out of reach.
The research was published in a peer-reviewed journal.
More information: Stéphanie Durand et al, Joint control of meiotic crossover patterning by the synaptonemal complex and HEI10 dosage, Nature Communications (2022). DOI: 10.1038/s41467-022-33472-w Journal information: Nature Communications
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