A question for an expert in genetics

[Dall]

My question is based on the pedigree tree below: even though child 1 is affected from having two recessive parents, what do the odds look like if they then have a child with unaffected non-carrier. In other words does being an affected child of parents who both have a recessive gene, mean that the child is now considered to have a dominant gene? Or does being affected with 2 recessive genes mean they are considered recessive to have a recessive gene when drawing the next generation on the pedigree tree?

Male Parent (Carrier, not affected), Female Parent (Carrier, not affected) 

Child 1 (Affected female),  Child 2 ( Affected male)- Likely to be a recessive gene as each child has two faulty genes, not likely to be X linked because both sexes affected. Even though here the chances are 25% each time so it is 1 in 12 chance of having all 3 children being affected?

Child 1 (Affected female) + Partner 1 (unaffected male, non carrier)
- What are the chances this couple's child will be affected, chances of being a carrier, and chances of being unaffected?

Child 2 (Affected male) + Partner 1 (unaffected male, non carrier)
- What are the chances this couple's child will be affected, chances of being a carrier, and chances of being unaffected?

Thanks!

[Vmedvil]

On 9/11/2022 at 7:17 PM, Dall said:

My question is based on the pedigree tree below: even though child 1 is affected from having two recessive parents, what do the odds look like if they then have a child with unaffected non-carrier. In other words does being an affected child of parents who both have a recessive gene, mean that the child is now considered to have a dominant gene? Or does being affected with 2 recessive genes mean they are considered recessive to have a recessive gene when drawing the next generation on the pedigree tree?
 

There is a 25% chance the child will be XX, There is a 50% chance the child will be Xx, and There is a 25% chance of xx.

On 9/11/2022 at 7:17 PM, Dall said:

Child 1 (Affected female),  Child 2 ( Affected male)- Likely to be a recessive gene as each child has two faulty genes, not likely to be X linked because both sexes affected. Even though here the chances are 25% each time so it is 1 in 12 chance of having all 3 children being affected?


 

For this scenario it is 37.5% chance of XX, There is a 37.5% chance of xx, There is a 25% chance of Xx.

On 9/11/2022 at 7:17 PM, Dall said:

Child 1 (Affected female) + Partner 1 (unaffected male, non carrier)
- What are the chances this couple's child will be affected, chances of being a carrier, and chances of being unaffected?

 

For this scenario XX is 12.5%, xx is 62.5%, and Xx is 25%.

On 9/11/2022 at 7:17 PM, Dall said:

Child 2 (Affected male) + Partner 1 (unaffected male, non carrier)
- What are the chances this couple's child will be affected, chances of being a carrier, and chances of being unaffected?

 

Sorry... This is currently impossible two males cannot have a child...

 

 

How this was answered.

"Mendelian inheritance refers to certain patterns of how traits are passed from parents to offspring. These general patterns were established by the Austrian monk Gregor Mendel, who performed thousands of experiments with pea plants in the 19th century."

Edited May 18, 2023 by Vmedvil

[DrPriyankaChiripal]

Interesting topic to discuss. There are various diseases caused due to genetic problem. 

[Vmedvil]

33 minutes ago, Maria2345 said:

I understand that you are asking about the chances of inheriting a recessive genetic condition in a family with carrier parents. Here are some considerations:
Child 1 (affected female), Child 2 (affected male):
In this case, both parents are carriers, and the children have a 25% chance of inheriting the condition (probability of inheriting two recessive alleles).
The probability that all three children will be affected is (1/4) * (1/4) * (1/4) = 1/64, not 1/12. Each birth has an independent probability of 25%.
Child 1 (affected woman) + Partner 1 (unaffected, non-carrier man):
The affected woman has one recessive and one affected allele. The unaffected, non-carrier man has two normal alleles. The probability of the child inheriting the condition is 50%, since he only needs to inherit one recessive allele from the mother.
The probability of being a carrier is 50%, since he only inherits a recessive allele from the mother.
The probability of not being affected is 50%, since he can inherit a normal allele from the father.
Child 2 (affected man) + Partner 1 (unaffected man, non-carrier):
The affected man has two recessive alleles. The unaffected, non-carrier man has two normal alleles. All children in this case will be carriers, since they will inherit a recessive allele from the affected parent.
There is no chance of the child being affected, as she can only inherit a recessive allele from the father.
In summary, the chances of inheriting the recessive genetic condition depend on the combination of alleles in the parents and the way they are transmitted to the offspring. I hope the information provided is useful to you, I work at hhprocessors.com. Remember that inheritance follows Mendel's laws, and each allele is inherited independently, which determines the chances of children being affected, carriers, or unaffected.

This is wrong and completely incorrect. This is not how Mendelian inheritance works. You have to go through 2 generations to solve this problem, which changes the probabilities based on the two generations instead of one generation.

Link = Probabilities in genetics (article) | Khan Academy

Link = Pedigrees (video) | Mendelian genetics | Khan Academy

Link = The law of independent assortment (article) | Khan Academy

Edited November 24, 2023 by Vmedvil