How long would it take for a novel alelle to be fixated in a population?

Probably much more than that is junk. Even the ENCODE people admitted that only 10-20% of the genome is under selective pressure which would be the preferred criteria for this thread. The other 80% does not appear to have sequence specific function. Either that, or it is invulnerable to deleterious mutations:On the Immortality of Television Sets: Function in the Human Genome According to the Evolution-Free Gospel of ENCODE | Genome Biology and Evolution | Oxford Academic

The important take home message is that Haldane's Dilemma is not a dilemma. He was just wrong. Slightly deleterious mutations can be removed from the population through selection (even through neutral drift), and alleles can be fixed in parallel, not one at a time. Selective sweeps also solve the dilemma.Even in inheritance systems that are the most unforgiving (i.e. asexual reproduction) we still see that there is no dilemma. It is called Muller's Ratchet, an effect where deleterious mutations build up in asexual populations. What scientists did was look at endosymbionts which are bacteria that can only live within host cells and are passed on from one host to the next. They compared the endosymbionts between host species which gives them a known time of divergence which can be used to measure mutation rates and fixation rates. What did they find?"A decrease in nucleotide substitution rates over time suggests that selection may be limiting the effects of Muller's ratchet by removing individuals with the highest mutational loads and decreasing the rate at which new mutations become fixed."
Background Primary bacterial endosymbionts of insects (p-endosymbionts) are thought to be undergoing the process of Muller's ratchet where they accrue slightly deleterious mutations due to genetic drift in small populations with negligible recombination rates. If this process were to go unchecked over time, theory predicts mutational meltdown and eventual extinction. Although genome degradation is common among p-endosymbionts, we do not observe widespread p-endosymbiont extinction, suggesting that Muller's ratchet may be slowed or even stopped over time. For example, selection may act to slow the effects of Muller's ratchet by removing slightly deleterious mutations before they go to fixation thereby causing a decrease in nucleotide substitutions rates in older p-endosymbiont lineages. Methodology/Principal Findings To determine whether selection is slowing the effects of Muller's ratchet, we determined the age of the Candidatus Riesia/sucking louse assemblage and analyzed the nucleotide substitution rates of several p-endosymbiont lineages that differ in the length of time that they have been associated with their insect hosts. We find that Riesia is the youngest p-endosymbiont known to date, and has been associated with its louse hosts for only 13–25 My. Further, it is the fastest evolving p-endosymbiont with substitution rates of 19–34% per 50 My. When comparing Riesia to other insect p-endosymbionts, we find that nucleotide substitution rates decrease dramatically as the age of endosymbiosis increases. Conclusions/Significance A decrease in nucleotide substitution rates over time suggests that selection may be limiting the effects of Muller's ratchet by removing individuals with the highest mutational loads and decreasing the rate at which new mutations become fixed. This countering effect of selection could slow the overall rate of endosymbiont extinction.What happens is that each slightly deleterious mutation adds to those already present until you hit a level where they are selectable. Think of it as the "straw that broke the camel's back". This shows that Haldane was wrong and there is no dilemma.

A single generation is all it takes. A generation with 1 million A alleles and 1 million B alleles followed by a generation with 999,999 A alleles and 1,000,001 B alleles is a change in allele frequencies.

There are other ways of copying text other than ctrl+c.It is really hard for us to read your mind. If there is something in the text that you want us to focus on you need to quote a small section and discuss why you think it is important.

If his assumptions are wrong then there isn't a problem to begin with. Of course, we can't blame Haldane for his mistakes because even he stated quite clearly that this was a working model that was surely wrong in some way. No one even knew how DNA worked back then being that DNA had only been discovered a few years before Haldane wrote that paper.Given what we know now, there isn't a dilemma. There never was.