Genetics and breeding question

Tarantula155

Arachnobaron
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Dec 1, 2012
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486
So I've been wondering, if I caught a spider from one side of the country and bred it with a spider from the other side of the country will their offspring have any advantages verse the inbreeding that occurs within range? Any possible mutations?

I have a female Phidippus audax that I've caught in Missouri and recently bred her with a male I found in New Mexico. I know the female being from Missouri where it's very humid, I'm sure she'd do horrible in desert climates like her mate, vise versa etc.

Anyone ever try this? Notice any differences from their offspring whatsoever?
 

Ranitomeya

Arachnoknight
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Oct 11, 2012
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250
There will be no higher chance of mutations--at least not in the scientific definition of the word--than you would normally encounter. Inbreeding has a lower effect on organisms with high numbers of offspring produced. The chances of encountering a beneficial combination of genes is much higher when there are more offspring, improving the chance that you have future generations that do not have the detrimental combinations of genes since those with it would be less likely to reproduce. You might get offspring that are better able to survive in either, you might get offspring that are less able to survive in either, or there might not be any effect.

An interesting thing with invertebrates is that their phenotypic expression, or what traits their genes produce, is very dependent on epigenetics. Epigenetics is the change in phenotypes resulting from modifying gene expression instead of genetic code. A great example would be bees. Workers and queens from a colony are genetic females that are often nearly identical in genetics, but how the larvae were fed results in different gene expression and resulting phenotypes. If epigenetics are responsible for their ability to survive in one environment or the other, you will likely see no effect from breeding two individuals coming from very different environments.

Now we can talk about how inbreeding depression and outbreeding depression can both be a result. If you introduce genes into a population by outbreeding, there is the chance that you are introducing genes that can cause the population's fitness to drop, which is outbreeding depression. In populations where inbreeding is not an issue because genes circulating are in no way detrimental, outbreeding can introduce inbreeding depression. If you introduce a detrimental recessive allele to a gene into a population, you won't see the immediate detrimental effects of outbreeding until inbreeding occurs and you have inbreeding depression.
 

Tarantula155

Arachnobaron
Joined
Dec 1, 2012
Messages
486
There will be no higher chance of mutations--at least not in the scientific definition of the word--than you would normally encounter. Inbreeding has a lower effect on organisms with high numbers of offspring produced. The chances of encountering a beneficial combination of genes is much higher when there are more offspring, improving the chance that you have future generations that do not have the detrimental combinations of genes since those with it would be less likely to reproduce. You might get offspring that are better able to survive in either, you might get offspring that are less able to survive in either, or there might not be any effect.

An interesting thing with invertebrates is that their phenotypic expression, or what traits their genes produce, is very dependent on epigenetics. Epigenetics is the change in phenotypes resulting from modifying gene expression instead of genetic code. A great example would be bees. Workers and queens from a colony are genetic females that are often nearly identical in genetics, but how the larvae were fed results in different gene expression and resulting phenotypes. If epigenetics are responsible for their ability to survive in one environment or the other, you will likely see no effect from breeding two individuals coming from very different environments.

Now we can talk about how inbreeding depression and outbreeding depression can both be a result. If you introduce genes into a population by outbreeding, there is the chance that you are introducing genes that can cause the population's fitness to drop, which is outbreeding depression. In populations where inbreeding is not an issue because genes circulating are in no way detrimental, outbreeding can introduce inbreeding depression. If you introduce a detrimental recessive allele to a gene into a population, you won't see the immediate detrimental effects of outbreeding until inbreeding occurs and you have inbreeding depression.
Thanks. Great reply, very informative!

Let's see if other users have first hand experience doing this and if they noticed any differences.
 

Ranitomeya

Arachnoknight
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Oct 11, 2012
Messages
250
@Ranitomeya I'd like to hear you expound further. Fascinating.
I'm going to assume you'd like me to explain more about epigenetics and give some examples.

Genetic expression can vary within individuals carrying the same copies of genes. This variation in genetic expression is caused by genes being turned on to produce the protein they code for or turned off so that the protein coded for is not produced. Genes can be turned on or off temporarily or permanently and the switches that turn them on and off are still being studied. There are on/off switches for genes that can only occur at gamete production; there are on/off switches that can only occur during early development; and there are on/off switches that can occur at any point in response to physiological stresses. There are many being studied that are trans-generational that we still have yet to understand.

For an example in epigenetics in insects, we can look at social Hymenoptera. You can see variations between siblings caused by the presence, absence, variation in concentration and frequency of presence of the hormone(s), and diet. You'll see morphological and behavioral differences as a result of modifications in gene expression. Queens and the different soldier and worker phenotypes in bees and ants are the result of the modification in gene expression and not only the result of variation in diet during the larval stage.

In honey bees, a diet low in royal jelly--the protein-rich substance given in large amounts to larvae destined to become queens--results in workers. The poorer nutrition changes gene expression to produce the phenotype of a worker rather than the phenotype of a queen. In addition to morphology, the worker honey bee's behavior is also the result of gene expression. For example, nurses and foragers are both worker honeybees, but they behave differently because certain genes are turned on and certain genes are turned off to modify behavior. Usually, nurses are the young bees and foragers are older bees nearing the end of their lifespan. If the number of foragers suddenly drop, the nurses will experience changes in gene expression and become foragers early. Whether or not this behavioral change is the result of genetic expression was determined by looking at the proteins being synthesized by the bees. Here's a paper: http://www.nature.com/neuro/journal/v15/n10/abs/nn.3218.html

In other insects, epigenetics can be used to explain the variation within a species. Examples include locusts and the change from solitary to gregarious morphology and behavior or the way mantises, stick insects, and many other invertebrates can change their coloration as they grow and molt either in response to their environment or other stimuli. Behavior and not just appearance in most invertebrates is literally coded in their DNA, much unlike humans are almost entirely dependent on learned behavior. Epigenetics allows invertebrates and most other organisms to adapt to varying conditions.
 

The Snark

Dumpster Fire of the Gods
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One aspect and but one question at the moment. The transition in humans from genetic programming, erectus, to usage of the frontal lobes, sapien learned behavior. What was the time frame?
 

Ranitomeya

Arachnoknight
Joined
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Messages
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One aspect and but one question at the moment. The transition in humans from genetic programming, erectus, to usage of the frontal lobes, sapien learned behavior. What was the time frame?
I haven't studied the history of human evolution much and I have to admit I might not have been paying a great deal of attention during the lecture when my biology course went over the history of humans and their origins. If I remember correctly, Homo erectus was already relying on learned behavior for tool-production.
 

The Snark

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Nod! Perhaps it is just that my curiosity was peaked in those same classes. One and only one animal on this ball of dirt that divorced itself from the genetic programming in response to environmental factors. From gene expression, or alternately, the prefrontal cortex was a product or byproduct of the penultimate advancement in it? Other animals show signs of primitive cognitive development above and beyond simple response functions, but...?
One of my ongoing conundrums, mental masturbation if you will. Excuse.
 

schmiggle

Arachnoprince
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If I may chime in...(though I think this thread has gone very off topic XD)

Most animal behavior is a combination of genetics, epigenetic, and learned behaviors. For example, even sea slugs, which don't even have a full-on brain, can learn that certain prey animals are unpleasant to attack and will avoid them in the future (and these kinds of learned behaviors can be found in even simpler animals, such as flatworms). Some "simple" animals show even more complex behavior: wasps can individually recognize each of their thousands of hive-mates by their face, much like humans, for example. Animals can also illustrate behaviors which are directly genetic or epigenetic (starvation in an ancestor leading to certain eating behaviors in offspring (epigenetic), or squids shooting ink when afraid (genetic)). That, I think, was fully discussed by Ranitomeya.

However, coding rules for behavior are more complex than those for literal parts. Large-scale organs always develop identically in a certain place as long as all genes function correctly and are turned on and off correctly. However, changes in behavior become probabilistic even in genetically identical organisms. Humans actually illustrate this perfectly: identical twins separated at birth share a 50% correlation for many behaviors (I saw this paper referenced, but I never saw the paper, so I don't know which behaviors). What this looked like anecdotally was that, for example, there was one pair of twins that separately developed the same odd way of scratching their nose and separately developed an identical word for it. 50% may not seem high, until you realize that the correlation among identical twins for height is 55%, and for schizophrenia (which has been definitively linked to genes) is 45% (I think--it might be as low as 40%). All of which is to say that behavior, even in humans, is largely controlled by genes, but is also influenced by the environment, in ways that are probably both genetic and neurological. We are far from divorcing ourselves from our genetic material; rather, it influences us in deep ways which are still not fully understood.

Another way that genetics influences behavior is in potential. Humans have to learn language, but we are genetically predisposed to do so--many parts of the brain are intimately connected with language. The sea slugs and wasps mentioned earlier follow a similar pattern. All of these species have the potential to learn a specific thing in a specific way, but that learning, and the behavioral changes that follow, does not happen until it is triggered by a certain event (hearing words enough times, encountering a distasteful prey item, or seeing another wasp's face).

Finally, most behavioral situations are probabilistic. A person becomes more and more likely to act on their anger as they become angrier, and their anger, chemically speaking, is a direct result of certain hormone concentrations in the brain. An ant is more likely to act alarmed as the concentration of an alarm pheromone it recognizes increases. Genetic pre-disposition largely determines what concentration of a hormone will be produced because of what stimulus, and these hormone concentrations largely influence behavior. In humans (and, I believe, in many other animals), I think some stimuli could be considered internal (probably not the right word, but whatever). A person feels themselves getting angry, and calms themselves down to avoid a problem. Calming oneself down is a stimulus also: it causes the concentrations of certain hormones in the brain to decrease.

I hope this is helpful in some way. Fundamentally, I think the idea of human uniqueness is problematic, and comes from a very deep misunderstanding of just how much we actually are influenced by our genes.
 

The Snark

Dumpster Fire of the Gods
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and comes from a very deep misunderstanding of just how much we actually are influenced by our genes.
Toss in the irrationality factor, found both genetically and in cognitive development. Said by some to be the fundamental building block of adaptivity. The RNA that tries to go sideways in the gel or the desire to experiment with an unknown just because you can.
 
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