Posted on 05/06/2011 8:56:43 AM PDT by Red Badger
A genetics research group working in a lab in Kansas, has succeeded in creating a new species of lizard by mating two distinct species of North American Whiptails, both native to New Mexico. The offspring, all females are not only fertile, but can reproduce by laying eggs that don't need to be fertilized, which means, they actually clone themselves.
Scientists have known for years that some species exist due to interspecies mating, the whiptail lizards have provided proof of that; they’ve been creating new species themselves for at least several hundred thousand years. What’s new is the process being manipulated by another species, us, Homo sapiens. Geneticists have been trying for years to create a new breed of pretty much anything by urging lab “volunteers” of differing species to mate with one another, not exactly earth shaking science when you consider a dog that tries to mate with a human leg. Efforts such as these are, not surprisingly, more often successful than not; the problem is, the offspring are usually infertile, such as mules, or too weak to survive. The trick has been to create a new species that is able to both survive and reproduce, because otherwise, it can’t really be called a new species if it only exists for the duration of one generation.
In a paper published in PNAS, lead researcher Peter Baumann of the Stowers Institute for Medical Research, describes how he and his team paired an A.inornata male with an A.exsanguis female resulting in six eggs; all of which hatched, resulting in young lizards that were more similar to the female than the male, save a bit of blue tint on the tails. Each also had four copies of their parental genes (normally there’s just two), three from their mother, the other from their father. They were also all female and all able to reproduce by cloning themselves.
Not only have the initial lizards survived and reproduced, so too have their offspring; the lizards are currently in their fourth generation, leading to the inevitable question of whether they should be given a name. Baumann is hesitant to do so as it’s likely to court controversy from the biology/genetics community as the new species hasn’t yet been given the opportunity to show that it can exist outside of a lab, though the team members certainly believe it’s capable of doing so.
More information: Laboratory synthesis of an independently reproducing vertebrate species, PNAS, Published online before print May 4, 2011, doi: 10.1073/pnas.1102811108
Abstract Speciation in animals commonly involves an extrinsic barrier to genetic exchange followed by the accumulation of sufficient genetic variation to impede subsequent productive interbreeding. All-female species of whiptail lizards, which originated by interspecific hybridization between sexual progenitors, are an exception to this rule. Here, the arising species instantaneously acquires a novel genotype combining distinctive alleles from two different species, and reproduction by parthenogenesis constitutes an effective intrinsic barrier to genetic exchange. Fertilization of diploid parthenogenetic females by males of sexual species has produced several triploid species, but these instantaneous speciation events have neither been observed in nature nor have they been reconstituted in the laboratory. Here we report the generation of four self-sustaining clonal lineages of a tetraploid species resulting from fertilization of triploid oocytes from a parthenogenetic Aspidoscelis exsanguis with haploid sperm from Aspidoscelis inornata. Molecular and cytological analysis confirmed the genetic identity of the hybrids and revealed that the females retain the capability of parthenogenetic reproduction characteristic of their triploid mothers. The tetraploid females have established self-perpetuating clonal lineages which are now in the third generation. Our results confirm the hypothesis that secondary hybridization events can lead to asexual lineages of increased ploidy when favorable combinations of parental genomes are assembled. We anticipate that these animals will be a critical tool in understanding the mechanisms underlying the origin and subsequent evolution of asexual amniotes.
Their idea of ‘perfection’ must mean “NO Males”.............
I read it twice and still dont get it. If the tetraploid females still need to be fertilized by a male, how are they cloning themselves?
Tetraploid means they have four sets of chromosomes, one set originally came from a male lizard. Since the eggs require only one complete set of chromosomes to be fertile, they are fertile from birth of the lizard that produces them. The subsequent offspring from these eggs, to their fourth generation, retain that four sets of chromosomes in their own genetic makeup. Therefore their eggs will be fertile and hatch without further introduction of male sperm............Does it make sense now?...........
“”Does it make sense now?...........””
What confused me was that I thought the mothers were triploid. But now a new question arises. If the mothers are tetraploid, the process of meiosis would produce diploid eggs (supposedly fertile) to create a diploid offspring. How are the offspring tetraploid?
Correction, What confused me was that I thought the EGGS were triploid.
It must be that the genes of a female are more flexible and therefore more adaptable for long term survival of a species, even if it's a new species..........
The following exerpt from a Wikipedia article on Parthenogeneis answers the question.
“Parthenogenesis is a form of asexual reproduction found in females, where growth and development of embryos occurs without fertilization by a male. In plants, parthenogenesis means development of an embryo from an unfertilized egg cell, and is a component process of apomixis.
Parthenogenesis occurs naturally in some invertebrate animal species (e.g., water fleas, aphids, nematodes, some bees, some Phasmida, some scorpion species, and parasitic wasps) and some vertebrates (e.g., some reptiles,[2][3] fish, and very rarely birds[4] and sharks[5]). This type of reproduction has been induced artificially in fish and amphibians.[6]
Normal egg cells form after meiosis and are haploid, with half as many chromosomes as their mother’s body cells. Haploid individuals, however, are usually non-viable, and parthenogenetic offspring usually have the diploid chromosome number. If the chromosome number of the haploid egg cell is doubled during development, the offspring is “half a clone” of its mother. If the egg cell was formed without meiosis, it is a full clone of its mother.”
Huh? What you say?
Anyone notice the logical fallacy in this ‘scientific’ article?
Here it is in a nutshell:
This type of reproduction is rare.
The two different species made one new species that is special.
Because there is no further outside influence from another set of genes being introduced during each new generation, we can use this animal for studies in different areas of research.
That there was no phallacy?.............
A tiger and a lion can produce fertile offspring - yet they are clearly two different and distinct species.
The measure of being your own species is not that you can not reproduce fertile offspring with any other population group : it is that you do not.
Tigers and Lions don’t mate in the wild, their ranges do not overlap anymore, and they are clearly distinct and different species.
Politics has nothing to do with it.
Looks like somebody has an obsession.
It’s a play on words.
Since the lizards in the article require no further male input to reproduce,,,,,,,,,,,,,,,,,,,,,,,,,,,
Mental masturbation cannot replace critical-thinking skills.
That's ONE opinion of what a "species" is. There are as many more opinions of "species" as there are biologists.
In the ornithological world, you're opinion is not held. As an example, a couple of decades ago, the yellow-bellied sapsucker was split into three species: yellowed-bellied in the east; red-naped sapsucker in the Interior West; and red-breasted in the Pacific Northwest. The differences in appearance is clinal: the farther west you go, the more red in the bird.
HOWEVER, all these "species" freely choose to interbreed where their malleable ranges overlap.
Many in the ornithological world still scoff at this split. They contend that these "species" are races (or sub-species), as they regularly (and freely) interbreed -- unlike the tiger/lion paradigm.
Interestingly, sometimes the prevailing winds change direction. The dark-eyed junco was once considered to be a bird of several species. But the American Ornithological Union and the American Birders Association decided otherwise many years ago. This group was "lumped." All the sub-species became one: the dark-eyed junco.
Politics has nothing to do with it.
If only that were so. Politics often has EVERYTHING to do with it.
As in the "science" of man-made global warming, govt grants are handed out to scientists who produce "interesting" and "novel" theories. In the ornithological world, interesting and novel mean a species split. It's an old joke in this world: splitting is glamorous and exciting; lumping is boring and pedestrian. This is why, with only the slightest DNA backing, new species spring out of sub-species. Sadly, lumping is almost unheard of now. Many ornithologists disagree with this, though. Here's another old joke in this circle: If today's split-happy ornithologists taxonomically classified humans now, they would without reservation split us into 4 (some say 5) species of contemporary human.
Here's one other political aspect to consider in this mad-dash to split races into species: some biologists claim this is what is known as "speciation in progress" and we're watching the Darwinian proof of it take place before our eyes.
On the other side of the political spectrum, others (even other Darwinists) claim that this is certainly NOT "speciation in progress" but capricious splitting of sub-species into full-blown species -- done arbitrarily, semantically, and underwritten with institutional (or grant) money.
This issue may never go away, but I can say this to you: The definition of "species" is as concrete as a passing breeze, and politics will ALWAYS play a role in determining what is and isn't a species.
Regards!
Ping to Jaz and George. This is almost an everyday discussion among my field co-workers. It's very telling: the more leftist they are, the more they defend splitting races into species. The more right they are, the more they defend lumping races into one species.
Just so we're clear: I'm a lumper! LOL!
Off to the sticks now. Be back in about 9 days!
Fly
Somewhere, Groucho Marx is chuckling.
Onan the utilitarian..........
You really need to find another obsession.......
A species is a group of distinct inter-reproducing individuals.
Great - now how much reproductive isolation is needed to “qualify”?
What IS clear, thus prompting my post: is that the ability to reproduce fertile offspring does not establish that two individuals are the same species: otherwise Tigers and Lions are the same species.
They are clearly distinct species via the definition of species - in that the two different populations are genetically distinct and do not reproduce together in the wild.
Yes, “lumpers” and “splitters”. I don't think there are any “lumpers” out there quite so zealous that they want to “lump” tigers and lions together just because of their ability to produce fertile offspring when paired together by humans.
One of the problems with applying definitions to things that are real and not ideals. Reality seldom conforms to neat groupings.
We all know that the “Romance” languages came from Roman Latin - and while we know that modern Italian derived from archaic Latin - there was no clear moment when Latin became Italian - or when Italian clearly became a distinct language from Spanish. Differences just kept accumulating until finally someone from Spain and someone from Italy could no longer converse freely - and neither one would understand someone speaking Latin.
Does a regional dialect of a language count as its own language? Some would “lump” it in with another language - others would “split” it into its own language.
How someone decides to define it doesn't change the reality one bit.
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