Inbreeding?

[Lorgakor]

First I would like to thank everyone for their responses, I am taking everything in and have learned alot. I did use the search button, I have been a member here for a long time and know exactly where it is located. I had other questions included in my post, so I thought I would start a new thread. And look, someone like Ray Gabriel has taken the time to come and give responses, which were not given in past threads.

Just to elaborate a little on my post. The species I am interested in 'possibly' breeding is P. metallica, which is why I asked about inbreeding. There hasn't exactly been an influx of slings of this species into Canada. There is no way to buy slings from different sacs (as far as I know). But the price has come down, and there are a couple of dealers who have managed to get some, so I was thinking about purchasing some slings with the intent to breed them when they mature.

Again, thank you all for your responses, you are all very knowlegable and I very much appreciate the information.

 

[Thoth]

For the effects of inbreeding, most mutant fruit fly lab stocks have been inbred for hundreds of generations with no serious ill effect. They survive quite well outside the lab (i've had infestations due to poor student handling that took months to get rid of).

Also all syrian hamsters in the US are descended from the same female and her 3 sons. Yet seem to do well.


The sickle cell anemia is not due to inbreeding but straight and simple natural selection. Those who had one copy survived long enough to breed. The fact having two copies of the gene killed the person is an unintended effect. (No real evolutionary reason why. Suprise nature is not perfect.) Other similiar cases is cystic fibrosis in northern europeans, One copy protects against bronchitis, two kills.

There was a paper published many years ago (trying to find it) which through various modelling it showed that inbreeding increases genetic diversity but does increase the frequency of unfavorable traits. The only reason I remember it is for the counterintuitive aspect of inbreeding increasing diversity.

My basic point while not ideal inbreeding is not the end of the world.

 

[billopelma]

Question two, is it possible to rear males and females into maturity at the same time with pokies? For example, once they are sexed, slow the males down and speed the females up?

One problem I'd be concerned with is that poec's, for me anyway, are notoriosly difficult to sex. By the time you figure out which one is what it may be too late, for the males anyway.

After reading all of this, it seems to be generally agreed that *if* indeed inbreeding did cause a problem in T's, it wouldn't show up for at least a few generations. Presuming a generation takes a year or two to produce, then adding a new bloodline every, say, 5 years should keep everything 'right'. It doesn't seem unreasonable to assume that new blood could be procured in that amount of time...

Bill

 

[AfterTheAsylum]

Well, I am pretty much cashed here. It's all a downhill battle for me... and thedarkfinder. Also, the ALL L. parahybana have come from 3 females or whatever... I could prove you wrong 30 times over, with genics too. And in addition, inbreeding defects, like thedarkfinder said, show up much later in life. You cannot deny genetics.

The Sickness

 

[Henry Kane]

Ok, obviously this is a touchy subject. Let's everybody calm down.
There are some very cut and dried posts (by a very credible hobbyist) in this thread that really back up one side of the debate a bit better than the other. I'd simply suggest re-reading with your shields and spears down this time. Perhaps even take all comments in stride and enjoy a healthy discussion or debate instead of allowing undue defensiveness and posturing to distract from the topic.

Hang in there with this topic and have fun. There is a lot to be shared and even more to be learned.

As for my comment on the topic itself, tons of the species we enjoy in the hobby today simply would not be here if it weren't for inbreeding.
Consider a somewhat isolated T colony in the wild. Is it not possible that offspring may breed with a parent, even commonly, to sustain numbers in the wild?

Take care.

Gary

 

[edesign]

HHHMMMM i thought breeding and reproduction were the same thing amybe i am wrong please explain the DIFFERANCE;P ;P

really boils down to personal interpretatin. To me..breeding problems are problems such as hemophilia, retardation, bad hearts, etc. Reproductive problems are those directly related to the ability to reproduce such as sterility, miscarriages, and such.

ALALALAALALA VERTIBRATES LALALALAALALAAL

Cmon some proof on INVERTS

Ray

ok...maybe i missed something here, quite possible...but I don't think you have said why invert genetics are any different than vertebrates. Then again, I have an electrical engineering background and not a biology/genetics.

 

[Scorpiove]

breeding problems do not necessarily equal reproductive problems. Look at Dalmations...they've been inbred for quite some time and they are known for bad hearts (and joints too i think?). This is a breeding problem. Look at the old royal English family back when they inbred a LOT...they had a lot of hemophiliacs. Why? Because hemophilia is a recessive gene (last I read...about 10 years ago in high school lol) and during inbreeding recessive genes have a much higher chance of being expressed in the newly created being using the same limited genetic pool.

is it just me or do you seem a bit confrontational? :? It might just be me...seriously

Having descended from part of the English royal family I know thats not true. The only part that has problems are the ones descended from Queen Victoria. Since all the royals in europe married her offspring their children aquired the problem. Inbred or not. I was doing my family tree and it became very confusing Since they did inbreed. Hemophilia only became a problem when Queen Victoria came along, they inbred before she came along too ya know . Also another part of my family most recent than my "royal line" (I descend from King Edward III) They were from West Virginia and I found 3 instances of inbreeding ranging from 2 cousin to 4th cousin. I'll have to go have a look at my tree for exact relationships heh.

Edit: Another small point is inbreeding is going to occur whenever any creature breeds since they are afterall the same species. For example everyone on this plantet is related in some way or another. Yes I know it may be 20th cousin or probably at the most 30th cousin. But still we are all related.

Edit 2: Lets not forget the god-awful mites. If there are just simply two (male and female) on a single cricket and you put it in your tank with the t and all of a sudden you have a mite outbreak of lets say 1000 mites. GAH horrible. Doesn't look like inbreeding bothered them any either.

Edit 3: lol I don't want to sound like a snob or you guys thinking I'm a snob since I revealed my blue bloodline . But chances are that about maybe 85% of this board is descened from some type of royal line aswell. You would never know but it most certainly true.

 

[GoTerps]

Also, the ALL L. parahybana have come from 3 females or whatever... I could prove you wrong 30 times over, with genics too.

So do it ! ? They were brought into the hobby as 3 eggsacs... and like was mentioned before, there is no guarantee the mothers of those eggsacs were unrelated.

Actually, I've heard that the A. geniculata stock we're working with now may all be from 1 of the original smuggled females (maybe 2). There were a couple of the orginal smuggled females that dropped sacs though. Anyone with more info here can chime in.

Soulsick... maybe you could start an experiment, since you've successfully captive bred T. blondi 16 times... right?

 

[edesign]

Edit 3: lol I don't want to sound like a snob or you guys thinking I'm a snob since I revealed my blue bloodline . But chances are that about maybe 85% of this board is descened from some type of royal line aswell. You would never know but it most certainly true.

i stand corrected on that point

don't feel snobbish...I'm decended from Spanish royalty

 

[Scorpiove]

i stand corrected on that point

don't feel snobbish...I'm decended from Spanish royalty

Well hello cousin the royal houses of europe intermarried many times. If you trace king edward III line back you find he descends from kings of france, spain, sweden, norway, russia. He descends from many royal families in europe. emperor charlemagne and so on. You even have genealogists trying to trace is line back to the emporers of Rome and the the pharoahs of egypt. Although the further back you get it gets kind of questionable. But that isn't until you start getting back to the emperors of rome. To bad I didn't descend from Queen Victoria she descends from most royal houses in the world one way or another . I know it doesn't mean much but its fun thinking about it.

 

[Brian S]

If it doesn't happen in nature all that often, you probably shouldn't do it n captivity though. Sure 3 generations may seem normal, but what about the 4th? Defects can lie in dormancy. What might happen if a 3rd gen inbred mates with a different 3rd gen inbred down the road?
T.S.

How would anyone truly know if it doesnt happen in the wild? Who knows if a females offspring doesnt come back to Mom and mate with HER one day. Now think about that
Naturally it is better to have genetic variations in our breeding but we know so very little about the life of a tarantula in the wild that we cant say if it does or doesnt happen in nature

 

[Socrates]

How would anyone truly know if it doesnt happen in the wild? Who knows if a females offspring doesnt come back to Mom and mate with HER one day. Now think about that
Naturally it is better to have genetic variations in our breeding but we know so very little about the life of a tarantula in the wild that we cant say if it does or doesnt happen in nature

:clap: :clap:
Very well put, Brian, and I whole-heartedly agree.

Until someone follows a wild tarantula around for many years (including her offspring), we'll never know WHAT goes on with whom when it's time to breed.

---
Wendy
---

 

[Crotalus]

Actually, I've heard that the A. geniculata stock we're working with now may all be from 1 of the original smuggled females (maybe 2). There were a couple of the orginal smuggled females that dropped sacs though. Anyone with more info here can chime in.

There were several adults for sale when they first showed up in the hobby so id think they were smuggled in fairly large quantities

 

[casesensative]

genetics are genetics no matter what type of living organism your dealing with, and even if you dont see it now, in the end, it will eventually have bad results.

 

[Thoth]

People are making the assumption that by inbreeding that bad traits will appear or develop. That is not the case barring a viable mutation event. What inbreeding does if there is a bad trait present it will increase the frequency of the trait and prevent it from being diluted out.

The example of hemophilia in English royalty shows this for the most part european was inbred and as Scorpiove until Queen Victoria introduced hemophilia into the mix everything was working out. Most tribal/clan based populations were probably inbred.

 

[Scorpiove]

Thoth is right. Lets look at egyptian royalty for a second. They were heavily inbred. We are talking brother and sister having kids together and those kids having kids together and half brother and sister having kids together and mother and son and cousins. I'm sure there were probably some problem in the line a few kids maybe having sever mental handicaps and other genetic deformities. But obviously a good deal of the off spring went onto become egyptian pharoahs (with good genes), and these are vertebrate animals we are talking about!

P.s. its possible to trace a line from King Edward III to the pharoahs although it may not be 100% accurate (1000 years back). While adding the pharoahs to my tree though I got an insant headach trying to add someone as the son and husband! I use a Genealogy program. Here is a little hint though Most of the royal family of europe is researched if you can trace a line back to one of these people you will beable to add several several more people(thousands) who have been researched by professional genealogists. and its very accurate too.

 

[edesign]

realize something new every day i feel a bit more educated...

now you got me wondering if i'm related to anyone important in Norway's history...I'm part Norwegian too.

 

[Swindinian]

I've got a few points and also queries.

Apologies that it doesn't flow or put forward a clear argument - hope that doesn't put you off.

Genetics isn't a simple subject!

So, surely, it IS useful to look at known examples where inbreeding has resulted in problems, including vertebrates - and use these to predict possible scenerios with captive breeding theraphosids in the hobby.

But bear in mind that one example doesn't equal what WILL happen in the hobby.

Surely the best way forward is to record and share our observations, and track our breeding records - develop a family tree of captive breeding. Know where your stock comes from.

If a problem arises in our hobby we can trace it back.

(Question:Would it be logical to assume that the greater the genetic diversity of a population, the more deleterious alleles could be present?)

'Inbreeding vigour' - it's possible we could have a higher proportion of healthy stock in captivity by maintaining lower genetic variability.

One major issue that people seem to neglect but is possibly equally, if not more significant to the future of our hobby, is the possibility of 'Outbreeding depression'.

Take this scenerio:

You receive a shipment of spiders, location of collection unknown, then obtain another group, again, with no knowledge of the origin of collection. You get the spiders appropriately identified, as the same species, so you breed them.

However, they could originate from disparate locations - populations that are genetically significantly different.

(question: is it safe to assume genetic divergence is equally proportional to morphological changes?)

They could possess comparable but different alleles (different forms of the same gene). This mix of alleles may prove to be deleterious when bred together.
Hyperthetical example: one allele helps the spider retain more moisture from the booklungs, it coming from an arid habitat. The other helps fight bacterial infection of the booklungs in the more moist habitat.
Mix them together and the book lungs don't moult out easily. (bearing in mind this is a simple hyperthetical example - sometimes genetic interactions are much more complicated, and harder to observe).

We could speculate whether this would come out in the first generation or many generations down the line.

End result is you are preventing inbreeding (preceived as a good thing) but have erronously created outbreeding depression.

Last statement/question:

I would guess that the more complicated an organism is, the more chromosomes it should have.

The more chromosomes it has, the more varieties of deleterious alleles it could potentially have.

Question: How many chromosomes do spiders tend to have?

Does it hold true that the less complicated the organism, the less complex the interaction is between the various alleles and various genes.

If so, we might find the theraphosid genetics turns out to be less inherently complicated than studying other organisms such as some vertebrates.

:?

 

[Thoth]

I guess Scorpiove, that would make you a distant cousin 1000 times removed.

Question:Would it be logical to assume that the greater the genetic diversity of a population, the more deleterious alleles could be present?

Yes, but the frequency of it occurring would very low.

question: is it safe to assume genetic divergence is equally proportional to morphological changes?

Yes and No, genotypic differences may or not lead to phenotypic differences. Look at dogs and wolves. You have different breeds of dogs which are genetically identical but morphologically very dissimiliar (daschund vs. greyhound) or you have a wolf and dog genetically different enough to be seperate species but some breeds of dog look very much like wolves. Or if you want an invertebrate example there are species of beetles which can only be differentiated by there sex organs. Then again several closely related organisms look quite different.

I would guess that the more complicated an organism is, the more chromosomes it should have.

Not true.

Does it hold true that the less complicated the organism, the less complex the interaction is between the various alleles and various genes.

No, it is suprisingly similiar among all eukaryotes.

Outbreeding depression is possible if it introduces an unfavorable trait to a healthy inbred population, could potential devestate it.

 

[GoTerps]

There were several adults for sale when they first showed up in the hobby so id think they were smuggled in fairly large quantities

Hi Lelle,

Or the orginal group was just handled in a very bad manner, with only money in mind.

And just because there were adult females for sale, doesn't mean those females contributed to what's in the hobby now... do we know if any were paired, died, etc..?

Or are we now only working with the offspring from the few females that were gravid when they were caught.

Eric