Rate of Spontaneous Mutations

travis · September 20, 2006

Does anyone have an idea or a link to information regarding
what the true rate of spontaneous mutation is in tomatoes?

Like ... at what rate could one anticipate something like
a spontaneous mutation occuring in a huge population
of a known to be stable red fruited tomatoes that
would result in a single plant bearing yellow fruit?

In other words ... how many plants of a single
cultivar would one have to grow in a single season
to anticipate a single spontaneous mutation
among that crop?

PV

Vince · September 21, 2006

I am not positive, but I think there is an equation to predict the amount of random mutations in a organism. It has been a couple of years since I took Biochemistry, but I think it depends on how big the living things genome is(how many different genes it has). If I have time and I can find one of my old books I'll look it up.

Vince

**carolyn137** · September 21, 2006

Vince and PV,

There is no ONE equation that predicts spontaneous mutation rates in general since the rates are gene specific.

And off hand I don't think I've ever seen specific rates given for different tomato genes.

It's easy to do with the viruses and bacteria I used to work with b'c they have such large populations, that, for instance, one can say that the rate is 10 to the minus 4 for Penicillin Sensitivity to resistance and on and on.

But with tomatoes, it's almost impossible to predict since the population sizes for a specific gene change are so small.

Also, spontaneous mutations can be either in the seed DNA or in plant cell DNA, called a somatic mutation.

PV, with regard to your specific question I or others would have to do the Googling to try and find some data, and, well, that's just not in my game plan right now.

I can tell you that over the years I've seen more DNA specific mutations than somatic mutations, and have seen the variety Green Gage, which is yellow, have one branch of red, and I know it goes the other way as well.

Yellow Riesentraube resulted from a single fruit on a plant with red turning yellow due to a somatic mutation.

And we know that WI 55, a red, threw a yellow sport, apparently with all yellow fruits, but I don't know what the mechanism was but assume it was a DNA mutation.

As to specific mutation rates for specific tomato genes, though, I don't have a clue, as I would for bacteria or viruses.

Vince · September 21, 2006

Forget what I said then. Listen to Prof. Carolyn. I only averaged a C+ in a Year of BioChem.LOL

Vince

psa · September 21, 2006

Phenotypic mutation rates are further decreased by the number of genetic mutations that have no effect at all, have no discernable effect, or are fatal. And even when a gene changes in a way that would have a discernable, survivable effect on the plant, it still has to be expressed, which may or may not happen depending on what other genes are present. Without discernability and expression, we won't even know to save the seed with the new genetic profile.

Then there are those of us who aren't as observant as we should be, and sometimes watch a plant all season without noticing that it is unique.

September 20, 2006	#1
travis Tomatovillian™ Join Date: Jan 2006 Location: Evansville, IN Posts: 2,984	Rate of Spontaneous Mutations Does anyone have an idea or a link to information regarding what the true rate of spontaneous mutation is in tomatoes? Like ... at what rate could one anticipate something like a spontaneous mutation occuring in a huge population of a known to be stable red fruited tomatoes that would result in a single plant bearing yellow fruit? In other words ... how many plants of a single cultivar would one have to grow in a single season to anticipate a single spontaneous mutation among that crop? PV

September 21, 2006	#2
Vince Tomatovillian™ Join Date: Jun 2006 Location: Riverside, CA Posts: 942	I am not positive, but I think there is an equation to predict the amount of random mutations in a organism. It has been a couple of years since I took Biochemistry, but I think it depends on how big the living things genome is(how many different genes it has). If I have time and I can find one of my old books I'll look it up. Vince __________________ Vince

September 21, 2006	#3
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	Vince and PV, There is no ONE equation that predicts spontaneous mutation rates in general since the rates are gene specific. And off hand I don't think I've ever seen specific rates given for different tomato genes. It's easy to do with the viruses and bacteria I used to work with b'c they have such large populations, that, for instance, one can say that the rate is 10 to the minus 4 for Penicillin Sensitivity to resistance and on and on. But with tomatoes, it's almost impossible to predict since the population sizes for a specific gene change are so small. Also, spontaneous mutations can be either in the seed DNA or in plant cell DNA, called a somatic mutation. PV, with regard to your specific question I or others would have to do the Googling to try and find some data, and, well, that's just not in my game plan right now. I can tell you that over the years I've seen more DNA specific mutations than somatic mutations, and have seen the variety Green Gage, which is yellow, have one branch of red, and I know it goes the other way as well. Yellow Riesentraube resulted from a single fruit on a plant with red turning yellow due to a somatic mutation. And we know that WI 55, a red, threw a yellow sport, apparently with all yellow fruits, but I don't know what the mechanism was but assume it was a DNA mutation. As to specific mutation rates for specific tomato genes, though, I don't have a clue, as I would for bacteria or viruses. __________________ Carolyn

September 21, 2006	#4
Vince Tomatovillian™ Join Date: Jun 2006 Location: Riverside, CA Posts: 942	Forget what I said then. Listen to Prof. Carolyn. I only averaged a C+ in a Year of BioChem.LOL Vince __________________ Vince

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September 21, 2006	#5
psa Tomatovillian™ Join Date: Aug 2006 Location: TriCities, WA Posts: 141	Phenotypic mutation rates are further decreased by the number of genetic mutations that have no effect at all, have no discernable effect, or are fatal. And even when a gene changes in a way that would have a discernable, survivable effect on the plant, it still has to be expressed, which may or may not happen depending on what other genes are present. Without discernability and expression, we won't even know to save the seed with the new genetic profile. Then there are those of us who aren't as observant as we should be, and sometimes watch a plant all season without noticing that it is unique.