Thursday, April 16, 2009

Why Hybrids Can't Reproduce - A Creationist's Observation

I love the intricacies of God's created order and am particularly fascinated with how he designed the means of defining the physical manifestations of life in this world. I'm talking about genetics.

I've often wondered about the lack of ability of many diploid hybrids to reproduce. But to give you the observation I came to, let me rebuild a good understanding of basic genetics for you.

First, there are specific genotypes observed among living organisms. Given that there are a couple of ways to define and use the word "genotype", I'll give the definition I'm using here in my own words: A genotype is a combination of genetic patterns that allow for a range of morphological diversity by interchanging different alleles at certain loci. If this is Greek to you, let me give you a metaphor:

Have you ever played that puzzle game where a story is written down with several blanks? These are often called Mad Libs. With each blank is a suggestion as to what type of word is expected there, whether it is a now, verb, adjective, etc. So you ask someone for that type of word and write down whatever they say. After you have filled in all the blanks, you read the completed story which has been made humorous because the words were random. Well, the structure of the story has already been determined. All you need to do is fill in different words to produce a slightly different story with the same structure. You go on to the next story and discover a different structure with different places for words to go. You can randomize the words as long as you stay within the structure, but you can't change the structure or the story won't make enough sense to be funny anymore.

The structure of the story is like a genotype. The words are the alleles. The locations of the words in teach sentence and paragraph are their loci (each location being a locus).

To continue the metaphor, since each organism receives its words from its parents it can only receive those words that its parents have to give. Within a genotype all combinations are possible, but because of environmental factors not all words survive over time. Only those words which can reproduce effectively can continue to be part of the story. So over time a population with a certain genotype will weed out the words that don't work for that period of time. This is called "speciation". This is where different species come from. Unfortunately, if the environment changes and certain words are lost within that population, then a species may become extinct because they no longer have the ability to adapt. This is what creationists mean when we say that speciation represents a loss of information rather than an increase in information.

Something that's helpful is to re-infuse populations with words from other species or sub-species. If it is a sub-species, then the offspring are typically able to reproduce. But if the words come from a different species within a genotype, then the offspring is called a hybrid and often cannot reproduce.

That's why I have wondered why, if they are of the same genotype, they cannot reproduce. I've finally realized the answer.

Species become species because different combinations of "words" or alleles are capable of survivable reproduction. Otherwise, those combinations will die out. When you breed different species together, you may produce offspring that are useful. For example, you may have hearty grain or you might have a mule that has the benefits of both a horse and a donkey. However, mules typically cannot reproduce. Therefore, in order to get more mules you have to breed more horses with donkeys. So why can't a mule reproduce, for example?

Is a mule a different species? Is a mule a different sub-species? Neither. It's a hybrid. It didn't become a species by the same process of natural selection that drives speciation, so it's not a species. It's not different breeds of the same species. It's a cross between two different species. However, the combination of words doesn't usually mix to make a creature that can reproduce. Sometimes, perhaps a hybrid can reproduce. However, if two mules could reproduce, they might produce an offspring that is more like either a donkey or a horse because "mule" is not a species per se. If you could breed a mule back with a horse or a donkey, you may get a horse or donkey with some qualities of the other species. If so, then perhaps some of the words long lost in a species could be restored toward the type, but I wouldn't think this to be very likely because the mule isn't a species.

Now let me tell you why this is important. There are two types of evolutionists: those who understand genetics and those who think they understand genetics. Those who understand genetics know that I'm right in a basic way. There's a sense in which there appears to be some flexibility in the structure of a genotype. However, science has not demonstrated such fluidity in structure that would account for a slow progressive change in a genotype over time. Rather, the evidence is that different species within a genotype maintain a fairly consistent genotypic structure with marked distinctions between genotypes. In other words, there's not a multitude of slight yet fundamental differences in genotype between species within a genotype.

In keeping with our metaphor, the evolutionist's claim is that the story is pretty much the same, but the structure of one sentence or another has been altered changing the gist of the story slightly. What I'm saying is that this hasn't been noticed. There is the occasional error where part of a sentence, or even a whole sentence, has been duplicated. This would be obvious and is obvious, but this doesn't represent a re-write of the sentence.

However, an evolutionist who understands this can't accept it. Therefore, the only thing the evolutionist can do is to propagate the notion among evolutionists who don't understand this that speciation represents these slight changes in genotype to the point where eventually one can call the type of organism a new genotype. The evolutionists who don't understand what I have addressed above think that the supposition they have been fed has been proven to be true when it hasn't.

Now there are levels of detail that I haven't even touched here like dipthoid reproduction and a genetic analysis of different levels of morphologically based taxonomy, but I hope I've made this understandable to you. When hybrids can't reproduce, we may think that perhaps it's because their genotypes have shifted far enough apart. Rather, it's because hybrids are not breeds within a species. A hybrid doesn't have the benefit of a species to contain the allele combinations that can survive and reproduce by actually surviving and reproducing.

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