The only people who benefit are the individuals who have lactase persistence.
Going by what I’ve read here so far, I’d say it seems He didn’t… Or at least didn’t have to.
Maybe you can explain what lactase persistence has to do with pooulations exposed to Malaria?
Actually having one copy is deleterious in the absence of the malaria parasite. It provides a net benefit only in malarial regions.
The variant is not in the lactase enzyme but is a defect in the control region that breaks the on/off switch. As I carefully explained it is NORMAL in mammals for lactase production to CEASE after weaning.
I thought we were talking about lactase persistence. So never mind.
Chris, in my medical practice, I routinely care for patients with hemochromatosis. You are correct that this mutation is believed to have had a selective advantage during the Neolithic era. As this article states:
Humans are tropical animals and climate is a major selective force on geographic variation in allele frequencies (Hancock et al., 2008; Laland and O’Brien, 2010; Veeramah and Novembre, 2014). Here we have shown that the geographic distribution of the C282Y allele for iron retention in contemporary Europe is associated with increasingly chilly and damp environments of human occupation during the Neolithic. Furthermore, dietary iron is necessary for effective thermoregulation—an important component of homeostasis (Lukaski et al., 1990; Beard et al., 1990, 1996; Brigham et al., 1996). When the near‐eastern Neolithic farmer migrated into Europe an iron‐poor diet was no longer simply a physiological stressor, it had become a separate source of selection. Under such conditions, natural selection would favor carriers of the C282Y allele, as those individuals would have higher survival rates and greater reproductive success than non‐carriers.
If a mutation breaks and on/off switch but results in a larger and smarter brain, is that a deleterious mutation?
Probably, around here.
Perhaps from the paper " Contact Transmission of Plasmodium falciparum in Fecal Deposits"
That’s my guess as well. If ID/creationists watched every mutation that happened in the human lineage starting with the common ancestor of humans and chimps, they would probably say that each and every mutation is deleterious even as humans evolved their bipedal gait and larger brains.
Hemochromatosis is an iron disorder in which the body simply loads too much iron. This action is genetic and the excess iron, if left untreated, can damage joints, organs, and eventually be fatal. [hemochromatosis.org]
In the case of the Black Death or the Neolithic period it would be interesting to see if anyone can show that hemochromatosis actually has enough benefit to outweigh the known detriments.
In the case of antibiotic resistance for instance the resistance is often due to a defect that disables the pathway used by the antibiotic, But there is only so far you can go by breaking things; that’s devolution. Similarly this has been observed in Lenski’s LTEE. Rather than evolution creating new things we see it breaking or deleting existing genetic information. This is the wrong way for Darwinism but compatible with Creationism.
Yes they are beneficial to each species and that’s why God created them.
What are beneficial exactly? DNA differences? It would be a waste to keep producing genes to digest chitin for humans but it turns out we have one functional copy and three pseudogenes with shared errors between other primates. DNA differences are quite important and paying attention to deactivated genes is really important too:
We might need that gene soon:
Chapulines and jumiles for everyone!
Since there are five variants and we still have one functioning copy, I think we’ll be okay!
5 posts were split to a new topic: Pseudogenes: functional or non-functional
Pseudogenes: functional or non-functional
I am asking you. If there was a mutation that broke an on/off switch but resulted in a beneficial change in brain size and function would you consider that a beneficial mutation?
It would seem that you would reject any change in DNA as being beneficial, no matter what it does. Am I wrong?