mardi 1 avril 2008

Chromosome numbers (first published on Communities dot com)

series---see comment for full index

Undisputed facts:

mammal a, say man, has 46 chromosomes
mammal b, say chimp, has 48 chromosomes
mammal c, say a lemur, has over 80 chromosomes.

They are all mammals, all chromosomes go diploid they are all supposed to have a common ancestor - *the first primate (none identified, but that is another problem)

Hypothesis I 46>48 or: 23*2>24*2

Stage one: 46>47
- by trisomy from one parent the new individual has the usual haploid set from another the haploid set has an extra chromosome, because both from one pair came along but this does not mean the new individual has 23 pairs and an extra foreign to pairs: it means that one of the 23 ordinarily pairs is trisomatic;

stage two: 47=47 or>46(=original 46)

if the individual formed in stage one couples itself with individuals that still have 46, the offspring will from that individual have either the ordinary haploid set or the set with two chromosomes for one pair-to-be, giving either individuals of 46 chromosomes or those that have the same trisomy as trisomic parent;

stage three: 47>48 or=47 or>46(=original 46)

Mendel's laws would indicate 25% 48 chromosomes, 50% 47 chromosomes, 25% 46 chromosomes But even so, the original pairs will not have changed. The two extra chromosomes will still be at one with two normal ones - one pair that should have been will be a tetrasomy;

stage four: 48=48?
How does this stabilise at 48, at a tetrasomy?

stage five: 48=22*2+1*4>24*2?
How does a tetrasomy become two pairs?

Hypothesis II 48>46 or: 24*2>23*2

stage one: 48>47 from one parent the offspring has ordinary set (1, 2, 3 ... 24), from other one with fusion (1/2, 3 ... 24) How does this hang together? 1 and 2 from the one parent should each have a centromere, while 1/2 from the other has only one. That is unworkable. End of hypothesis II, I think. The stage three 47>46 is not likely to happen at all.**

Including mammal c - and that must be in order to account for all mammals - means accounting for this difficulty not only once, but several times.

update, March 21/April 3:

Hypothesis III 46>48 or: 23*2>24*2, but by fission, not trisomy.

Stage one, 46>47?:
from one parent a chromosome has been inherited divided into two. Problem: it had only one centromere part, and each chromosome needs one in mammals (poultry have microchromosomes without centromeres, mammals have not).

Adjusting hypothesis:
the half that did not get one from whre it should got a centromere by chromosome crossing. Problem: that means it has gained a bit, but also lost a bit, whether from the chromosome's partner or from quite another chromosome

Correlate: that means there is chromosomal unbalance in this individual. Chromosome N meets either chromosome Na or chromosome Nb. It cannot meet both. Say it meets chromosome Na, that means chromosome Nb is superfluous and potentially damaging. And single. There is no guarantee whatsoever it will get along where chromosome Na goes in terms of ovula or spermatozoa. Supposing the mammal that has this superfluous chromosome outside the pairs will live to develop such and hand them on.

Stage two, 47=47 (or >46): same problem as for hypothesis I. Plus the fact that it may be Nb that joins with the N from non-mutated parent.

Stage three, 47>48 (or=47, or>46):
Here is where possibly Na meets Na and Nb meets Nb. Though it is extremely unlikely. And Where functions of Na and Nb diversify rather than having the functions of N plus a non-useful N+function.

Stage four, 48=48:
In order for this to happen, the individual from Stage three must meet another individual that also has the new chromosome couples Na+ Na and Nb+Nb. Which is even less likely in that first crucial generation. But where this to happen, stage five were no problem.

Hypothesis IV, 48>96 or 2*24>4*24>2*48:
Polyploidy is not observed in mammals. Poultry and lizards, as well as fish have been observed to give rise to triploid individuals, either infertile or parthenogenetical females. Batrachians have tetraploid and octoploid varieties (notably of a kind of salamander). But mammals are strictly diploid. Probably the placental implantation gets disturbed when the chromosome number is too diverse between mother and offspring. Poultry, lizards and batrachians have no placentas.

Stage one, 2*24>4*24 (or rather 3*24, if the production of gamete was correct from other parent) will therefore not happen.

Stage two, if stage one had happened, would be one gamete from tetraploid parent, 2*24 meeting one from ordinary parent not mutating, i e 1*24 would end the line, because the result would be, again, 3*24, i e an individual outside all future sexual reproduction. Or the extremely unlikely chance of meeting another 2*24 straight away, preserving overall 4*24 and making it synonymous to stages two, three and four.

Stage five, 4*24>2*48:
Here we are talking near impossible. Or forget about "near". Here it is a question of not one, but 24 tetrasomies diversifying to each two pairs.

Overall criticism: we do not find mammal populations (as far as the present author knows) with stable tetrasomies. Still less with half the genome in tetrasomies and the other half diploid. We do not find mammal species diversifying even like 46>48 or 48>46 within known observation. **

races (breeds, therefore populations) have been diversified as much as any mammal within the historic observation man has had over dogs, for however long it is both species have existed. A dog has the same chromosome number as a dog.

The only suspicions would be man 46 alongside apes (chimps, gorillas, orang utangs) 48 and horse 48 alongside Przewalski's horse 46. But these have not diversified within known historic observation like dog breeds. Their diversification is only presumed by evolutionists. What Darwin observed on ring species in terms of dove species in Europe and possibly finches on Galapagos Islands would therefore seem to be limited to species indirectly but fertilely interbreedable by sharing same chromosome numbers. Furthermore, Wikipedia which gives a lot of species constants for animal species does not include chromosome numbers, which is a species constant. Why? Because drawing attention to chromosome numbers might raise doubts about evolution, I suspect.

*but see update on okapis
**diversifying within human observation means diversifying in the timespan observed by us
update: here's an article where is claimed evolution could have been disproven but hasn't

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