# Thread: How can I marry two G25 coordinates?

1. ## How can I marry two G25 coordinates?

I was wondering if there is an easy procedure to derive the expected coordinates of one parent, if you have the coordinates of the other parent and the child of the couple.

2. I posted a script for that in the first page of the stickied Shell commands and R scripts for working with G25 thread.

3. ## The Following User Says Thank You to Standardized Ape For This Useful Post:

Liquid (06-29-2021)

4. You can get approximations, but heritability depends on many factors, so you will never get the actual coordinates.

Apart from using R, you can simply apply simple mathematical formulas, easy to solve with a spreadsheet for example:

Father=2*Son-Mother

Or if you prefer: Father=(Son+Son) - Mother

You can also use PCA, imagine where one parent or the son would plot, choose some close individual samples near that point and make averages of them. Itīs suposed that a son would plot near the middle point between both parents (is my case, but I have seen different cases).

What I tell you, even if it is not something very reliable, can help you to get an idea of ​​how the coordinates of the parents whose coordinates could be could be.

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chocoholic (06-29-2021),  fabrice E (06-28-2021),  okarinaofsteiner (07-04-2021),  rober_tce (06-27-2021)

6. Originally Posted by mokordo
You can get approximations, but heritability depends on many factors, so you will never get the actual coordinates.

Apart from using R, you can simply apply simple mathematical formulas, easy to solve with a spreadsheet for example:

Father=2*Son-Mother

Or if you prefer: Father=(Son+Son) - Mother

You can also use PCA, imagine where one parent or the son would plot, choose some close individual samples near that point and make averages of them. Itīs suposed that a son would plot near the middle point between both parents (is my case, but I have seen different cases).

What I tell you, even if it is not something very reliable, can help you to get an idea of ​​how the coordinates of the parents whose coordinates could be could be.
I have thought of that formula but since I have no idea how G25 coordinates are derived, I thought it wouldn't work. Do you know what the accuracy is when used on known G25 coordinates of Father, Mother and Son, i.e. (Son actual - Son estimate)/(Son actual) = ??

7. Originally Posted by Standardized Ape
I posted a script for that in the first page of the stickied Shell commands and R scripts for working with G25 thread.
Is it based on the Father=2*Son-Mother formula or something more mathematically elaborate, can you comment on how accurate the estimate is?

8. Originally Posted by Liquid
Is it based on the Father=2*Son-Mother formula or something more mathematically elaborate, can you comment on how accurate the estimate is?
You could say it's that formula as it's simple linear interpolation. The accuracy is dependent on how noisy the real coordinates are but generally the worst outcome is just 2% of something unusual.

9. ## The Following User Says Thank You to Standardized Ape For This Useful Post:

Liquid (06-30-2021)

10. Originally Posted by Liquid
I have thought of that formula but since I have no idea how G25 coordinates are derived, I thought it wouldn't work. Do you know what the accuracy is when used on known G25 coordinates of Father, Mother and Son, i.e. (Son actual - Son estimate)/(Son actual) = ??
Well, as I already told you, unless you get the real coordinates of the G25, these are not but simple methods to get approximations.

How accurate is all that? Little in general, although it depends on the individuals, but all these methods can give you an idea about how some of your parents coordinates could be.

As you understand, I cannot give you a figure or percentage that would express "accuracy" in this.

11. ## The Following User Says Thank You to mokordo For This Useful Post:

Liquid (06-30-2021)

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