breeding

[Ray Gabriel]

It is also possible that there are relatively benign mutations cropping up, such as different colors, smaller or larger stature, ability to breed more successfully in captivity (a secondary quality dependent on some as-yet-undefined primary mutation), and others.

When these arise, the enthusiasts who possess the effected individuals must make a value judgment about whether or not they are worth conserving. That judgment, of necessity must be based on personal beliefs and priorities, and I'm not going to go there. It is important for them to understand their options and the working principles involved, however, so they can make an informed judgment, not one based solely on knee jerk reactions or muddled thinking.

Colour is in the eye of the individual, and when you talk about size we must first know the complete natural variation within a population just because it falls outside of the "norm" does not mean it is in breeding or any other genetic problem.

We dont even know if our spiders have adapted to a captive enviroment so are changing to suit?

in the 30 odd years i have been keeping spiders we now know tonns more maybe 900%more than we did, in reality we still only know 1% if that of what there is to know,

JFC we dont even have the taxonomy worked out yet and people are trying to predict 100 years down the line of inbreeding.


go to a tarantula colony (works better on groung dwellers) stand in the middle and try to work out where the males will come from, understanding that spiders are thier own worst enimies, and then tell me colonies are not inbred ( a clue here is the distance to the next colony),

Ray

[Ray Gabriel]

It seems to me that Rick C. West actually did a small experiment with inbreeding some species of African tarantula over several generations and found that with each successive generation of inbreeding, various "bad" characteristics became more and more prevalent. I think he even published the results either in the BTS Bulletin or in the ATS Forum Magazine. Perhaps someone else would wish to look it up and do a "book report" on it.

I have been told that it was an Asian species, and/or a Grammastola species, and that it was one brother sister mating which decided that there was a problem with inbreeding.

I to would like to see if this has been published.

But since then other people have inbred species cannot rember the guys name but it was on P. murinus in the BTS journal, no problems there.

I have done it with P, regalis for a few generations no problems

Ray

[Ray Gabriel]

I would just make a few points generally about inbreeding (i.e. not specifically related to Ts)…

1. Inbreeding ‘in nature’ is widespread and common. Indeed it is a consequence of one of the main mechanisms of speciation – look up ‘Founder Principle/Effect/Theory’.

2. Is it ‘bad’? Well ask any group of geneticists or evolutionary biologists and you wont get a consensus of opinion because the research that has been done is expansive and conflicting. For every paper that you’d care to site I’ll find you a contradictory one (I’m talking of peer reviewed ‘scientific’ papers in mainstream journals here). There is quite convincing evidence that it can be beneficial in the long-term – deleterious gene effects appear to be more common in first few generations; such individuals are quickly ‘weeded out’ by natural selection leaving in subsequent generations a genetically ‘fitter’ population compared to an outbred population (deleterious recessive genes are effectively removed from the population genome in the first few generations; thereafter even the incidence of deleterious gene expression is lower compared to a ‘normal’ outbred population i.e. they are ‘fitter’ than a ‘normal’ population.).

3. The deleterious genetic effects that can occur with inbreeding tend to be ‘catastrophic’ i.e. the embryo fails to grow at all or dies before it has fully developed so in the case of Ts most of the negative effects will only be apparent within the egg sac. The slings that emerge are likely to be as ‘healthy’ as any.

4. ‘Culling’ strikes me as an inherently bad idea. As has been pointed out in other posts, on what criteria do you do it? Indeed how do you know how to play ‘God’ by imitating natural selection? Natural selection is not a ‘guiding hand’ – there is no direction, no ultimate goal, it chops and changes and is constantly going on. Keeping Ts in captivity is subjecting them to a variant of ‘natural selection’ anyway (remember all of those unexplained deaths?) – if they are surviving your husbandry (and are therefore ‘adapted to their environment’) who are you to say that particular individuals should be culled because of some other criteria that you’ve decided upon – if you are aiming for a genetically ‘healthy’ population then you should be MAINTAINING that variability NOT reducing it by culling.

5. A more specific point here…



Why not? There is no difference. Sexual reproduction is the SAME though-out; the ways in which it is achieved is the only aspect that you cannot compare and that is irrelevant here. How are you defining ‘complex’? There are many known examples where ‘simpler’ animals have far more genetic material than more ‘complex’ ones such as us humans. More is know specifically about the genetics/reproduction of the ‘simple’ fruit-fly than anything else but because there is no inherent difference in the mechanics of it all by inference this knowledge can be applied to humans.
Theraphosids are going to be no different to fruit flies or humans in terms of genetic mechanisms. No one is ever going to study the genetics of Ts (DNA sequencing for taxonomic purposes excepted) because the generation length is just too long – the favoured tools (species) for the geneticist have very short generation times so that results can be quickly seen. So, the favoured choices are fruit-flies, zebra fish and mice – if the mechanisms weren’t comparable to humans I doubt we’d be studying them to the degree that we are.

I’ll leave it there with my comments but would just say that this topic generally (not just in relation to Ts) is one that is awash with misconception and misinformation in the public domain. However, you wont get a definitive answer from the scientific world either! Personally I have no problem with it.

Nick

Cheres Nick,

Dont agree with all your points but a very well balanced post. You are dead right about the full scientific view ask 2 genetesists and you get polar replies.

Ray

[Stanley A. Schultz]

I find it rather repugnant that someone in your position ...

... I think an apology is in order to those people you may have offended? ...

Alright! That's enough!

It's time the moderators pulled the plug on this thread if not on your ability to post further inflammatory messages.

I chose to ignore your "SIGUE HEIL" posting (and you couldn't even get that correct; it's "Sieg Heil!") for the good of the thread, but even after a warning (http://www.thebts.co.uk/forums/showp...4&postcount=33), you can't mind your manners. You do not do your countrymen proud.

I am not a psychiatrist, a psychologist or even a priest. I will not attempt to deal with your personal, emotional baggage.

I, however, AM out of here!

[Ray Gabriel]

You do not do your countrymen proud.

Four of the seven PMs and emails i had thanking me for my comments were from people who dont actually post up on this site (but do visit and read) , possibly because they dont have the confidance to....yet (and confidance is something that can take years to get) One of which IS one of my countrymen (woman).

In speaking up for the "undesirables" against your comments, i dont think i have to apologise for anything now i know it was not just me who was offended.

Sorry you have taken this stance when all you had to do was retract your comments, and now you can see it was not just me. Just one small point, after your comments here do you think that the crippled, imperfect, slow, small or otherwise undesirable individuals, basicly not "quality" people will still want to buy the latest edition of your book?

Believe it or not i was actually trying to give you a hand out of the hole you had been digging, by giving you the chance to apologise and retract your statement I think you missed it, but it might not be to late..........its up to you.

I would still love to hear how you can tell a bad DNA spiderling from a good one

Ray

[Mark Pennell]

et al

This is an extremely interesting thread and the although most of the debate is on track there is enough here to warrant locking thread.

I remind everyone of rule 4:

(4) Please do not post any profanity or slanderous remarks. Naming shaming and personal attacks will not be allowed. If you have a grievance with someone or a company, dealer etc. contact the BTS directly. Such postings will be edited or deleted. The Admin and Moderators are here for this purpose.

Now, it seems of late I am or my mods are having to step in far to often for my liking. It always seems to be on the longer topics. However I don't like to be heavy handed in moderating and prefer that users are their own mods and conduct debates in a civil and respectful manor.

It is so easy to skip through a reply - reading it but not fully digesting its contents and sub consciously only picking on the words that offend you.

Then in the heat of the moment posting a reply that is not warranted. Can I please ask that you take time to read replies, and if at first it seems offencive or upsets you, just take deep breath and re read and just give the benefit of doubt- that what is written may not be written in the context you first thought, and ina round about way be actually supporting your views.

This thread will remain open for now.

Regards
Admin

[wesley flower]

hi mark i think it is about time this thread was closed if you dont mind me saying. i set up a thread basicall asking for info and giving my opinion. i am sorry to have caused problems on his site but i cannot account for other peoples actions.
thanks for your co-operation in this matter
kindest regards
wes

[Phil Rea]

5. A more specific point here…

Why not? There is no difference. Sexual reproduction is the SAME though-out; the ways in which it is achieved is the only aspect that you cannot compare and that is irrelevant here. How are you defining ‘complex’? There are many known examples where ‘simpler’ animals have far more genetic material than more ‘complex’ ones such as us humans. More is know specifically about the genetics/reproduction of the ‘simple’ fruit-fly than anything else but because there is no inherent difference in the mechanics of it all by inference this knowledge can be applied to humans.

And the fact that Drosophilia melanogaster only have four chromosomes, and pretty large ones at that

No one's debating that the laws of genetics are different for spiders. Of course thay aren't, but specifically that we do not have the knowledge to be able to speculate.

Your point about generation length is a good one, and something that is relevant to tarantulas specifically. It's difficult to know how this could be overcome.