MACROevolution vs MICROevolution - what is it?

I have brought this up before, but I want to present it here again for your consideration. It is the technique breeders use called recombinant inbred lines (aka. RILs). If your position were true, that it only takes isolation and inbreeding for several generations to produce new species, then RILs should produce numerous new species... but they don't.Here's how it works (this is for organisms that can self-fertilize):1. Two parents of interest, that are usually highly heterogeneous, are interbred and grown to seed.2. A large number of seeds are collected and planted for the next generation (this is called the F₁ generation).3. F₁ plants are selfed (pollen from the same plant is used to fertilize the ovaries) and seeds from each F₁ selfing are collected separately and become the F₂ generation. ** This is the isolation step. From here on out, each independent line is completely isolated from the other lines.4. F₂ plants are selfed and seeds collected separately and become the F₃ generation.5. The process typically continues for 6 - 10 generations and the final generation would be knownas the F_n generation.The image below diagrams the process: ** The process also works for organisms that cannot self-fertilize. In that case siblings from each generation are crossed, as shown above. Animals can be bred in this manner and, for example, is how laboratory mice are produced.The results of this extreme inbreeding is highly homogeneous lines with inbreeding coefficients >.95 and even approaching 1.0 (an inbreeding coefficient of 1.0 would indicate an identical/clonal population). This would mean that if a F₁₀ individual produced 1,000 seeds, the plants that grew from those would be virtually identical genetically - all 1,000 of them. There would be almost no variability in that F₁₀ population. This would be the true "end of evolution by loss of genetic information" that you insist on.RIL populations are usually quite large, containing several hundred individuals (300 is kind of the excepted minimum population size for good statistical power), all with unique, high homogeneous genotypes. Yet none are new species, none are reproductively isolated from the others. Why? There is no more efficient method of partitioning genetic diversity than recombinant inbred lines, it is the most extreme example of isolation, inbreeding and genetic drift (which you refer to as random selection) possible. Why does it not produce new species?Hint: all the genetic material in the parents still exists in the F_n population, but is just distributed among individuals rather than being contained in a single breeding pair. It must take an addition factor to differentiate those individuals into separate species. What could that factor be... maybe m*******? (Thanks to David Jay; this is a great idea to hide letters of a word so that the person you are having a discussion with has to guess what the word might be )I would guess you don't really see the significance of what I presented above, but it demonstrates beyond a reasonable doubt that isolation, inbreeding and genetic drift are not sufficient to produce new species. There must be another factor involved.HBDEdited by herebedragons, : changed sub-title

I'm pretty sure it's you that doesn't understand the difference between a gene and an allele... Source?HBD

Pray tell... what are these 4 types of alleles that exist inside a gene?HBD

Did you even watch the video you referenced? Not a very technical presentation, but it certainly doesn't say anything about: And I see nothing in the video about drift...Where are you getting your information????HBD

Don't you consider drift to be "random selection"? Only one seed from each cross is used to generate the next generation. That is extreme drift, ie. "random selection".I am pretty sure you don't view selection in the same way the rest of us do. I don't have time now to go back and dig up your statements about selection, but you have previously dismissed the roll of natural selection and put the emphasis on isolation, inbreeding and drift. Maybe you have changed positions and I missed that part of the discussion?So describe how you think the outcome of recombinant inbreeding would be different if at each step you grew up 50 individuals in each line and selected from that 50 an individual for some particular characteristic (each line having a different character selected for).The end result would still be highly homozygous, inbred populations; they would just have selected characters rather random characters. How would it be different?HBD

No idea what your point is...Yes plants are much different than animals...You can create RILs with animals too, but instead of using self crosses, you use sibling crosses. http://www.informatics.jax.org/silver/chapters/9-2.shtml

quote:

---

One begins with an outcross between two well-established highly inbred strains of mice, such as B6 and DBA in the example shown. These are considered the progenitor strains. The F1 progeny from this cross are all identical, and thus in genetic terms, they are all interchangeable. F1 hybrid animals are bred to each other to produce a large set of F2 animals. At this generation, siblings and cousins are no longer identical because of the segregation of B6 and DBA alleles from the heterozygous F1 parents.

---

HBD

Nope.Recessive traits can be lost due to drift, but so can dominate traits.

Uhmmm...Are you expecting me to present a source showing "loss of genes"? OR are you trying to find one??I have no idea what point you are trying to make... on just about anything you have said in this thread.

I will point out a couple more things about this Selection would be after the initial cross, the F₁ progeny. Breeders don't usually select for particular traits to begin the F₂ generation because they actually want the distribution to be random. Each of the F₂ individuals used to create the lines are isolated (meaning they no longer mix genetically with other lines) at this step - after selecting them from the F₁ progeny. AT the end of 10 generations of inbreeding, each population or line is almost completely homogeneous. More so than what would ever happen in nature in 100 generations. Each founding population has 1 individual (or 2 in the case of sibling crosses). There is no more severe of a bottleneck / founder effect possible than n=1 (or n=2 for sibling crosses). It is an extreme (the most extreme) example of the scenario which you are presenting. Each line will have its own set of unique characters, whether those characters are directionally selected or not, they WILL be differentiated to the maximum degree. Whatever character is selected (whether by random or by choice), that line will differentiate for that character and will become homogeneous for that character.It is the scenario you are presenting, just an extreme version of it. If those independent lines are going to speciate, there is a missing factor.HBD

Yes. See Message 578 for more info.

I will come back on later and explain in detail the comparison between the two processes. So let me get to that before you respond. Thanks.HBD

Well... seeing as how Faith has NEVER argued that "new kinds come into existence" and nothing I've said in the last day has any thing to do with "new kinds coming into existence" your point is even more obscure.It seems you think you have a winning hand when you don't even know what game we're playing."Full house! nines over tens!!!"Uhmm... we're playing Euchre."HBDEdited by herebedragons, : No reason given.

I will call what I see as your scenario the Faith Speciation Hypothesis or FSH. Whether we are talking about actual new species or just varieties, breeds or whatever, we need to go from one original species and eventually have multiple modern species, varieties or breeds whatever terminology you wish to use. However, if your claim is that your scenario only leads to new breeds and not new species (or what we recognize as species) then it is really quite meaningless as an explanation for the diversity of species.I will refer to Recombinant Inbred Lines as RILs.----1. In the FSH scenario, there was originally a single, presumably highly heterogeneous breeding pair (from the ark).The RIL scenario also starts with a single, highly heterogeneous breeding pair.In both cases, it is presumed that the parents were chosen because of particular traits. In FSH, it would be traits that would allow survival in the post flood world. The RIL parents are chosen because of some trait of interest, such as disease resistance, high yield, etc. Typically, one parent has the trait, the other does not. It can also be a combination of traits.----2. In the FSH scenario, this single breeding pair must reproduce until a suitable sized population forms to allow a daughter population to split off. During this initial period, the population will quickly lose heterogeneity until the population is large enough to begin random mating. This will also have the effect of distributing the original alleles throughout the population so that selecting unique combinations of alleles will become less and less likely. In other words, the population, as a whole, will become more homogeneous. The larger this initial population becomes, the less likely it is that a daughter population will have a unique mix of alleles.In the RIL scenario, progeny of the original pair are selected immediately and not allowed to interbreed. This keeps the population heterogeneous. Each progeny of the first cross will have a unique mix of genes, no two will have the same combination. The F₁ population will be highly heterogeneous both at the individual genotype level and on the level of the population as a whole.The selection process in the RIL scenario ensures that every line will have a unique set of genes and alleles and that each line will be different than the parents. The FSH does not; daughter populations could be representative of the parent population and result in an identical or very similar population.----3. FSH: Daughter populations are chosen at random for a specific environment. The combination of alleles they have may or may not be suitable for that environment. Thus, in this scenario, it may take several daughter populations before a suitable match of genotype to environment is found. The problem is, that daughter populations in this scenario are fairly limited.RIL: Daughter populations consist of a single individual or breeding pair and are also selected at random. The environment is constant between daughter populations, but there are relatively unlimited numbers of daughter populations, limited only by the number of offspring per generation.How long would it take to produce 10 daughter populations in the FSH scenario compared to the RIL scenario?Also, you should not object to the environment not being different in the RIL scenario, since you dismiss natural selection as a mechanism of change and have stated that it is only necessary that allele frequencies change.----4. FSH: daughter populations are isolated from the original population and from each other.RILs: daughter populations (individuals or pairs) are isolated from the original parents and from each other.----5. FSH: inbreeding within the daughter population causes increased homogeneity and the small population size causes increased rate of drift which increases the odds that alleles at low frequency are lost and alleles with high frequency are fixed. Homogeneity is limited as eventually the population will grow large enough to begin random mating.RILs: inbreeding causes homogeneity to increase rapidly since every generation operates at maximum inbreeding rate. Fixation and allele loss happen at the maximum rate possible.No possible scenario in the wild could generate homozygous populations faster than selfing or sibling mating. Any randomness to the mating, meaning the less related a breeding pair is, the longer it will take to fixation and homogeneity. I could show you how this works mathematically, but I don't suppose you would be too enamored by my efforts.----6. FSH relies on random selection of initial population, moderate levels of inbreeding, and changing allele frequencies to bring about a new form or species. End result is populations of moderately homogeneous individuals with a new set of allele frequencies compared to the parent population.RIL relies on random selection of initial breeding pair (or individual), maximum levels of inbreeding, and rapid fixation of alleles and changing allele frequencies. End result is a highly homogeneous population with a new set of allele frequencies compared to the parent population.---How are these methods different and why does the FSH scenario supposedly result in the formation of a new species (breed, variety or whatever) and RILs do not?To be fair, RILs do result in unique traits. But no one would want a population based on a RIL. The RIL population is used to identify key gene regions associated with a desirable trait. Once this region is identified, a RIL may be back-crossed into a more suitable genetic background. For example, a RIL may have a desirable level of disease resistance but have really poor yields. This could be crossed into a variety that has poor disease resistance but very good yield. You would then screen the progeny of the back-cross for those desirable qualities and hopefully, the region that confers disease resistance is incorporated into the variety that has good yield without disrupting the desirable qualities of that variety.RIL populations guarantee the outcome you predict of small, inbreeding daughter populations. It happens in just a few generations, at a much faster rate than could ever happen in a wild population. It is the founder effect on steroids.Changing allele frequencies due to isolation and homogenization is not sufficient to create new species. If it were, it would be happening all the time.HBD

The populations that result from that type of scenario may be distinctive and may have characteristics that distinguish them from each other, but that's not enough. It cannot go far enough to create separate species. They will just be different forms of the same species. Of course they are. But they don't become distinctive, separate species by simply changing allele frequencies. It doesn't work that way.So if what your scenario is trying to explain is how to make new varieties of the same species, big woop. There's not much controversy there. But the more important problem is to explain the origin of new species, and simply changing allele frequencies doesn't work for that.HBD

I just spent several long posts describing a situation that establishes beyond a reasonable doubt that inbreeding and changing allele frequencies doesn't generate new species. Because you can't take the time and energy to understand it doesn't change my argument. Why doesn't it happen in RIL populations where the inbreeding is as intense as possible. No natural population experiences the extent of inbreeding that a RIL population experiences. If that were true, then it should be happening in RIL populations... and it doesn't. We don't get new species forming even in hyper-increase-in-homozygosity situations. You "see that I don't understand it" because I am pointing out that your hypothesis is wrong? "Something" happens based on changing allele frequencies? Based on homogeneity? What could that be? What changes in a homozygous population prevents it from interbreeding with the parent population?I could make 1,000 RIL lines from a single parental pair and inbreed them until they were 99.9% homozygous and I guarantee that everyone of those 1,000 lines would still back cross with both of the parental lines. How could that be if you are right and all it takes to generate genetic incompatibility is inbreeding and changing allele frequencies? ABE: It is possible that a mutation in a few of the lines would prevent crossing, but that would be rare.So... how did FSH produce:horses with 64 chromosomes and donkeys with 62 chromosomes (inter-fertile -same "kind")----
... and in the fox "kind":Red fox = 34 chromosomes
Tibetan fox = 36 chromosomes
Kit fox = 50 chromosomes
Bengal fox = 60 chromosomes----
... and in the mouse "kind"Mouse = 40 chromosomes
Rat = 42 chromosomes??It doesn't work that way.HBDEdited by herebedragons, : No reason given.