Haldane's Dilemma: Resolving Beneficial Mutation Rates

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In summary, the conversation discusses Haldane's dilemma, which states that the rate of beneficial mutations cannot account for the time between the first hominids and humans. This dilemma has been disputed as invalid due to incorrect assumptions made in the calculations. With corrected calculations, the dilemma is resolved and the cost of natural selection disappears. This information comes from a rebuttal on the Talk Origins website.
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heliocentricprose
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http://en.wikipedia.org/wiki/Haldane's_Dilemma
This paper states that rates of beneficial mutations can not account for the time that has passed between the first homonids and humans. Has this been resolved? How?
 
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  • #2
I think this statement on the wiki page sums it up "The neutrality and factual accuracy of this article are disputed."

The rebutal - "Haldane's "cost of natural selection" stemmed from an invalid simplifying assumption in his calculations. He divided by a fitness constant in a way that invalidated his assumption of constant population size, and his cost of selection is an artifact of the changed population size. He also assumed that two mutations would take twice as long to reach fixation as one, but because of sexual recombination, the two can be selected simultaneously and both reach fixation sooner. With corrected calculations, the cost disappears (Wallace 1991; Williams n.d.). "

http://www.talkorigins.org/indexcc/CB/CB121.html
 
  • #3


Haldane's Dilemma is a well-known problem in evolutionary biology that was first proposed by British geneticist J.B.S. Haldane in the 1950s. It refers to the challenge of explaining the relatively slow rate at which beneficial mutations can accumulate in a population, compared to the vast amount of time that has elapsed since the first hominids appeared on Earth.

The Wikipedia article on Haldane's Dilemma does not provide a definitive answer to whether this dilemma has been resolved, as it is an ongoing topic of debate and research. However, there have been several proposed solutions and explanations put forth by scientists.

One possible solution is that beneficial mutations may not be as rare as previously thought. With advancements in genetic sequencing and analysis, scientists have discovered that many mutations that were once considered neutral or deleterious may actually have a slight beneficial effect on an organism's fitness. This means that the rate at which beneficial mutations accumulate may be higher than previously estimated.

Another explanation is that natural selection may act more strongly on beneficial mutations in certain circumstances. For example, in small populations or in rapidly changing environments, beneficial mutations may be more likely to survive and spread than in larger, stable populations.

Additionally, recent studies have shown that beneficial mutations may have a cumulative effect, meaning that multiple small beneficial mutations can add up over time to produce significant changes in a population. This may help to explain the slow but steady evolution of complex traits in humans.

It is also important to note that Haldane's Dilemma primarily applies to large, complex organisms like humans. In simpler organisms with shorter generation times and larger population sizes, beneficial mutations may accumulate at a faster rate.

In conclusion, while Haldane's Dilemma remains a challenging question in evolutionary biology, there have been various proposed solutions and ongoing research that shed light on the rate of beneficial mutations and the evolution of complex traits. It is a complex and multifaceted issue that continues to be a subject of study and debate in the scientific community.
 

1. What is Haldane's Dilemma?

Haldane's Dilemma is a concept proposed by British geneticist J.B.S. Haldane in the mid-20th century. It refers to the apparent conflict between the observed rate of beneficial mutations in organisms and the time it would take for those mutations to spread throughout a population.

2. How does Haldane's Dilemma relate to evolution?

Haldane's Dilemma is relevant to the theory of evolution because it highlights the potential limitations on the rate at which organisms can evolve through the accumulation of beneficial mutations. It suggests that the rate of beneficial mutation may be too slow to account for the diversity and complexity of species we see today.

3. What is the current understanding of beneficial mutation rates?

The current understanding of beneficial mutation rates is that they are relatively rare and occur at a low frequency compared to neutral or harmful mutations. This is supported by studies in various organisms, including bacteria, fruit flies, and humans.

4. How can Haldane's Dilemma be resolved?

There are several proposed solutions to Haldane's Dilemma, including the concept of "synergistic epistasis" which suggests that beneficial mutations may have a greater impact when they occur in combination with other mutations. Another proposed solution is that the rate of beneficial mutations may have been higher in the past, during periods of rapid evolution.

5. What are the implications of Haldane's Dilemma?

The implications of Haldane's Dilemma are still a subject of debate among scientists. Some suggest that it calls into question the ability of natural selection to account for the complexity of life, while others argue that it simply highlights the need for more research and a better understanding of the mechanisms of evolution.

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