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CrateDane t1_j4fvene wrote

It's not genes that are recessive or dominant, it's variants (alleles) of genes. A recessive allele is generally a gene that doesn't work, but if your other copy of the gene still works you still have enough activity to be unaffected. Changing that to a dominant allele isn't trivial. I can't come up with any examples of that happening quickly in evolutionary terms. On longer timescales it's easier, like if the gene product goes from acting as a monomer to a dimer and the broken allele then makes the dimer inactive - then the loss of activity can be enough to leave heterozygous individual affected.

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Furrypocketpussy t1_j4grax1 wrote

This is wrong. Some genes can be recessive but not affect the person if the other gene is able to meet the functioning threshold (like make enough of some enzyme), however at times just one recessive gene is enough to cause a disease or other phenotype problem (think a gene that produces a mutant protein that your body can't get rid of). Thats why there are heterozygous diseases

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CrateDane t1_j4gu7y6 wrote

> however at times just one recessive gene is enough to cause a disease or other phenotype problem (think a gene that produces a mutant protein that your body can't get rid of).

That's not a recessive gene. Firstly, it's not genes that are recessive, it's alleles. Secondly, what you're talking about there is a dominant allele.

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Furrypocketpussy t1_j4j1fbt wrote

Alleles are variants of genes. And no, still talking about recessive. Sickle cell, as an example, is a recessive disease and is still expressed in heterozygotes

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CrateDane t1_j4kg8y3 wrote

Well no. Full-blown sickle cell disease only affects homozygotes, and as such is considered recessive. But the heterozygotes do still have a different phenotype than either homozygote in some ways. That means in those respects the allele is not recessive at all. When it comes to malaria resistance, it's more of a dominant allele.

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Furrypocketpussy t1_j4n4ueo wrote

Idk what mental gymnastics you going through to term a recessive disease "dominant". Sickle cell heterozygotes are just in between full blown sickle cell and normal, thats just codominant expression but the disease is still recessive because if it was dominant then heterozygotes would have full sickle cell. Need to inform yourself before making bogus claims online

https://medlineplus.gov/genetics/condition/sickle-cell-disease#:~:text=Inheritance&text=This%20condition%20is%20inherited%20in,and%20symptoms%20of%20the%20condition.

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CrateDane t1_j4n6mu3 wrote

Read your own source:

>This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations.

Your source does explain that it gets complicated when there are, for example, two different kinds of mutations in the two copies of the gene. That obviously goes beyond the simple categorization of recessive vs. dominant.

Other sources make the definition even clearer, like this:

>sickle cell anemia, which is defined as homozygosity for the sickle hemoglobin (HbS) gene (i.e., for a missense mutation [Glu6Val, rs334] in the β-globin gene [HBB])

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AdEnvironmental8339 t1_j4zcmav wrote

Hey i want to ask, if the person has 2 alleles , 1 positive with sickle cells another is a normal function allele.

So is the sickle cell allele still working and you make false proteins but with the another allele still works normally then you still can be alive because your blood now consist both false hemoglobins and normal hemoglobins ( and the normal hemoglobins is in sufficient amount for you to be alive ? ).

I thought at first if an allele is reccessive and another one dominant then the reccessive allele will be locked , only the dominant will be working or switch ON. So whats wrong can you please explain..

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