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Author Topic:   Ratio of Deleterious Mutations to Beneficial Ones
Percy
Member
Posts: 22394
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.1


Message 3 of 35 (719314)
02-13-2014 6:57 AM
Reply to: Message 1 by PlanManStan
02-12-2014 6:59 PM


Hi PlanManStan,
There must be a mistake in his program because he says this:
The default selection pressure used in this example (six children per female, four of which are selected away every generation),...
Two surviving children per couple is all it takes for a population to replace itself and would never end in extinction.
--Percy

This message is a reply to:
 Message 1 by PlanManStan, posted 02-12-2014 6:59 PM PlanManStan has replied

Replies to this message:
 Message 4 by PlanManStan, posted 02-13-2014 7:22 AM Percy has replied

  
Percy
Member
Posts: 22394
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.1


Message 7 of 35 (719321)
02-13-2014 8:18 AM
Reply to: Message 4 by PlanManStan
02-13-2014 7:22 AM


So the next thing you have to know is how he's connecting his mutation rates to the "2 of 6 total offspring survive". That he even mentions such a number makes me think he's structured the problem solution incorrectly. The proportion of offspring that survive should be a function of the mutation rates, not something that is specified.
Also, specifying the number of total offspring (6) is arbitrary. If only 1/3 of offspring survive then an average of 5 total offspring per couple means eventual extinction, 6 total offspring means stasis, and more than 6 means eventual overpopulation.
Look at it another way. Researchers have measured the point mutation rates of many organisms, including humans. It probably ranges from around 1 to a few hundred point mutations per reproductive event, depending upon the mutation rate for the organism and the size of its genome.
Mendel's Accountant says that using the mutation rates researchers have measured results in extinction, so what is Mendel's Accountant trying to say? I can only guess that Mendel's Accountant is saying that since we're not extinct that researchers must have mismeasured the mutation rates. My own guess is that the Mendel's Accountant program has flaws.
Are you a programmer? The program itself can be found at Mendel's Accountant. Someone must have mentioned this program here before because I apparently downloaded it a couple years ago. It's written in Perl and is tiny, far smaller than the software for this discussion board. I doubt it has any of the sophistication they claim, particularly since it arrives at conclusions that are at odds with reality. But if you're a programmer we can look through it together and figure out if what it's doing makes any sense.
--Percy

This message is a reply to:
 Message 4 by PlanManStan, posted 02-13-2014 7:22 AM PlanManStan has replied

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 Message 8 by PaulK, posted 02-13-2014 8:24 AM Percy has seen this message but not replied
 Message 10 by PlanManStan, posted 02-13-2014 8:53 AM Percy has seen this message but not replied
 Message 11 by herebedragons, posted 02-13-2014 9:25 AM Percy has seen this message but not replied

  
Percy
Member
Posts: 22394
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.1


Message 32 of 35 (719467)
02-14-2014 10:26 AM
Reply to: Message 26 by Faith
02-13-2014 10:13 PM


Re: Selected against
I think a general definition of a deleterious mutation is where the organism is less successful at contributing offspring to the next generation than it would have been without the mutation.
This means there are varying degrees of deleterious. A mutation that causes failure to live long enough to reproduce means the organism contributes no offspring to the next generation. A mutation that shortens the life of an organism means it has a reduced period during which it can contribute offspring to the next generation. A mutation that makes it less competitive means it would be less able to look after its offspring, or less successful at finding a mate. And so forth.
Humans provide a poor example of the effects of less severe deleterious mutations because of family and social group support and because of modern medicine.
--Percy

This message is a reply to:
 Message 26 by Faith, posted 02-13-2014 10:13 PM Faith has not replied

  
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