There have been a number of conversation threads occurring on the forums discussing variations in fig cultivars such as leaf variegation, fruit coloration, etc. appearing from time to time, the how's and the why's and so forth. This is aside from the conversations discussing the potential for new common cultivars deriving from fig caprification.
There is a pretty nice explanation of what takes place in plants undergoing rapid growth as in the case of growth occurring at fig nodes when cells found at the nodes are undergoing rapid growth to produce new leaves, stems/branches or fig. In order for this growth to take place cellular DNA is rapidly being replicated / synthesized. It is during these processes that chance or externally induced alternate sequences in the replication process occur which could result in a set of genes suddenly producing variegated leaves, stems and figs. Random or induced changes that, once introduced into a gene sequence, would be propagated forward into subsequent generations of cells and become part of the new gene sequence for that variety... It's also possible that, as in the case of a non variegated Jolly Tiger, the small gene sequence change that was somehow introduced into the original non variegated Jolly Tiger that produced the leaf variegation in the first place, might be corrected during subsequent rapid DNA replication / synthesis at a downstream node resulting in the loss of that variegation in all cells replicated from that 'corrected' DNA strand in its future generations.
here is the link to the article:
http://lifeofplant.blogspot.com/2011...plication.html
Here are a few diagrams extracted from the article that shows the DNA replication and synthesis processes.
Its worth noting that sequence errors / changes can occur for a variety of reasons and considering the complexity of the processes discussed, it is amazing that they don't occur more frequently. In many cases, errors in DNA sequencing results in disease and death of affected host cells. In some cases where changes result in minor differences with no negative impact, the changes are simply retained.
A virus could POTENTIALLY impact a fig plant and its physical appearance by means of a viral attack vector wherein the virus injects in genome into a host cell. "Once a virus is in a cell, it will activate formation of proteins (either by itself or using the host) to gain full control of the host cell, if it is able to. Control mechanisms include the suppression of intrinsic cell defenses, suppression of cell signaling and suppression of host cellular transcription and translation processes. Often, it is these cytotoxic effects that lead to the death and decline of a cell infected by a virus. In its most benign form, its conceivable that a plant cell infected with virus dna could only have minor changes in gene sequences that will result in small changes to proteins governing leaf or fig fruit coloration, shape, flavor and so on."
Here is edited excerpt from another source which describes how genetic code can be altered.
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"Sometimes genes are deleted or are in the wrong place on a chromosome, or pieces of genes are swapped between chromosomes. As a result, the gene may not work or may otherwise affect the host cell.
"Point mutations" alter the genetic code by changing the letters in the codons -- the three-symbol genetic words that specify which protein to make . This can change the protein (which may impact / govern leaf coloration, fruit taste, etc).
Original message: SAM AND TOM ATE THE HAM| What it does | Kind of point mutation | Example of altered protein |
| Frameshift mutation | Message starts in the wrong place | AMA NDT OMA TET HEH AMS |
| Stop codon | Prevents part of the protein from being made | SAM AND TOM |
| Missense mutation | Causes an amino acid substitution | SAM AND TOM ATE THE DAM |
| mRNA splicing mutation | Portion of message is left out, leading to a shortened protein | SAM THE HAM |
See also: https://history.nih.gov/exhibits/genetics/sect1a.htm