?

Log in

No account? Create an account
 

Speciation and Genome Evolution

About Recent Entries

Что может дать ДНК-анализ аберрантов? Aug. 4th, 2007 @ 02:16 pm
wolf_kitses

На форуме Союза охраны птиц России обсуждали необычного молодого дятла, снятого VictorT 6 июля с.г. в Балашихе. http://www.rbcu.ru/forum/showthread.php?p=18099#post18099 , верхний ряд картинок.

Вроде бы похож на молодого большого пёстрого, но пёстрая грудь и белые каемки (полосатость) на чёрных плечах настолько засмущали коллег, что даже возникла идея что это гибрид большого пёстрого и белоспинного дятлов (D.leucotos). Такие гибриды раньше находили один или два раза а сейчас в Фенноскандии они наблюдаются чаще из-за деградации популяций белоспинного дятла (особенно в Финляндии). Для сравнения «нормальный молодой» с этого же места приатачен последним в верхнем ряду картинок.

Во всяком случае, на гибрида большого пёстрого и сирийского дятла (D.syriacus - ещё одна близкая форма, практически полувид), он совершенно не похож. Была бы промежуточная окраска крайних рулевых, розовый поясок на груди, и много чего ещё.

Вот гибрид большого пёстрого и сирийского дятлов, но взрослый (самая нижняя картинка). http://woodpeckersofeurope.info/?q=syrian_woodpecker


May. 25th, 2007 @ 01:41 pm
wolf_kitses

Системы распознавания "свой-чужой" и ренессанс биологической концепции вида
http://docs.google.com/Doc?id=dcw4nhcn_1ggssgz


Jul. 30th, 2005 @ 06:45 pm
medicmandieemt
Im selling a super informative book that I used last year in my zoology class....actually the prof only had us read one excerpt which was disappointing cause I read the rest on my own (pleasure reading I know!) but anyways its good for inciting biology related debates and in class, an excellent source for research papers!



1. Name of textbook-The Nature of Life-Readings in Biology
2. Student or Instructor's book? student
3. Author(s) forward by Lynn Margulis and Dorian Sagan (its a compilation of bio essays)
4. Publisher Great Books Foundation
5. Edition n/a
6. ISBN # 1-880323-86-9
7. Condition of book new
8. Any supplimental materials (i.e., study guides, code cards, MyLab, CDs)n/a
9. Price I bought it for 80 but will sell it for 35 (price is negotiable)
10. Links to your auctions n/a

The cover of the book is green with a monkey on it.....

Any questions or offers please AIM me at doremimanda or email me at doremimanda@aol.com or comment here

New FAMILY of frogs was discovered in India Jul. 4th, 2005 @ 02:20 am
triturus
Fantastic!

New frog from India was considered to be a member of new Anuran family:

http://pharyngula.org/index/weblog/comments/odd_little_frog/
http://www.nature.com/nature/journal/v425/n6959/full/nature02019.html
http://images.google.com/images?q=tbn:m360WGQUSDYJ:www.nature.com/nature/journal

This cute little guy is Nasikabatrachus sahyadrensis, a new species and a member of a new family of frogs recently discovered in India. His closest relatives are found in the Seychelles, far away in the Indian Ocean, which dates their separation way back in the Mesozoic. The discovery is cool for another reason:

Just how significant is the discovery of another family of frogs? Only 29 families are known, encompassing the approximately 4,800 known species. Most of these families were named by the mid-1800s, and the last discovery of a species of frog belonging to a new family, as opposed to merely a taxonomic rearrangement, was in 1926. All others date to the 1700s and 1800s, making this a once-in-a-century find. Moreover, according to fossils and evolutionary ‘clocks’ devised using molecular data, families of frogs are about as ancient as orders and superorders of mammals, having diverged from one another during the heyday of the dinosaurs in the mesozoic era (251-65 million years ago).

Nasikabatrachus sahyadrensis Biju and Bossuyt, 2003, Nature, 425: 711. Holotype: BNHS 4202, by original designation. Type locality: "Disturbed secondary forest near a dardamom plantation at Kattappana (09˚ 45´ N, 77˚ 05´ E), altitude approximately 900 m), Idukki district, Kerala, Western Ghats, India".

I could not even imagine that such fantastic animals still can be found!
Current Mood: crazycrazy
Current Music: Gloria!

The Smithsonian goes to the Dogma May. 31st, 2005 @ 12:55 pm
meleah
I'm surprised no-one's mentioned this here yet - has anyone noticed that The Smithsonian is showing an intelligent design film?

the original NY Times article annoucning thisCollapse )
(that's copied and pasted here to save you the hassle of registering on the site)

All of which seems perhaps above board except for the stated policy of the institution that "Personal events (i.e. weddings, etc.), fund raising events, and events of a religious or partisan political nature are not permitted." And if you've paid any attention AT ALL to the IDist crap, you'll know perfectly well that rather than being a 'competing scientific theory' as they so often bleat, it is in fact wholly a politcal exercise, yet another extension of the many-headed Hydra that is the frightening facist religious right in this country and now around the world, hellbent on rocketing us back to another fucking darkage.

For those curious, here is the overly large and very inclined to crash your computer preview for said film. And before you start on 'but it doesn't seem that bad' and 'that's a NASA scientist' let me say, firstly, don't get me started on fucking physicists, and secondly, its pretty damn clear that what is being intended here is the usual crap - a dissertation on how terribly 'unlikely' it is that 'random chance' (and therefore, by implication and the usual misunderstanding, misdirection and misinformation, evolution) is responsible for the existence of that pinnacle of nature, man(and yes, I use the term advisedly)kind. Here are much better reasoned arguments than I can provide right now as to why this is wholly unacceptable, if you needed convincing.

Were it just the money, as this implies, then here is both an offer, and very sensible take on the situation. I too, belive the great benefactor of the Smithsonian to be rotating in his grave at the perversion, and prostitution, of his vision.

And for the final sucker-punch, the terrifying blogger here has nicely pointed out, for those of us who may be mystified by the sudden defection of one of the pre-eminent scientific institutions in the world: "the Smithsonian depends for over 80 percent of its funding on the American federal government (approximately 67 percent from direct appropriations and over 13 percent from grants from federal agencies) and its new projects require the approval of Congress. An insider suggests that the US government is leaning on the venerable science institution to behave better toward people who want to talk about intelligent design".

The recent, and very disturbing trend to science-by-jury is bad enough, but outright partisan governmental interference in Science, not simply in the governance of ethics, but in the actual decisions as to what truths are to be accepted and disseminated is completely and utterly unacceptable.

(x-posted like all hell)
Current Mood: angryangry
Other entries
» Hi!
My name is Nick Poyarkov, I am studying in Moscow State University (Russia) and currently I am interested in speciation and evolutionary biology of European Newts (Triturus) and related urodelian taxa.

What I want to ask you - I wonder if anybody discussed here the problem of subspecies definitions in zoology or biology generally? Actually nearly every biologist have heard about Biological Species Concept (Ernst Mayr's works etc., etc.) and it is a wide spread point of view that the SPECIES is the universal (species in zoology was thaught to be nearly the same as species in botany, for example) and the only "real" taxonomical category, while all lower (subspecies) and higher (genera, familis etc.) categories were considered to be not real but artificial categories for diversity systematization. However, several questions arise...

1) Rather phylosophical one - what means "reality" for a category? How can we determine if the taxonpomical category is real or not? What are suitable criteria?
2) If species is considered to be a "real" taxonomical category - we have individual organisms (they are "real" for sure), we have local populations (also seems to be real because they is limited gene flow among such clusters), we have geographical populations (real again, because we have nearly no gene flow among different geogrpahical popualtions in current time scale or what?), we have subspecies (mostly considered to be hypothetical categories not presented in reality) and we have real species? So, why subspecies are not real then?
3) If they are real - do you know any conceptual ways to separate "the real" subspecies and subspecies which were described only for practical needs?

I will highly appreciate any comments or advises! If you know any publications where the problem of taxonomical categories is discussed (especially some conceptual ideas concerning interspecific differentiation, phylogeography, subspecies criteria etc)- it would be great to get a reference!

Thanks in advance,
Yours sincerely,
NICK
» Plants Rewrite Textbook Genetics
In a very interesting Nature paper this week, Lolle et al. report that Arabidopsis plants have been found to rewrite their parent's DNA and revert to that of their grandparents. Specifically, about 10% of hothead mutants homozygous for the hothead mutation were found to revert back to their grandparent's wildtype sequence. Evidence was found that this happens to other loci as well. They provide a convincing set of data to demonstrate that it is not likely contamination causing the reversions, and if demonstratd in other labs, this will add a previously unthought of mechanism to modern genetics. The authors propose that some sort of RNA store may be used as the template for rewriting the DNA, but it's not clear what the mechanism is at this point. Here's a decent news article on this: http://cmbi.bjmu.edu.cn/news/0503/104.htm
» t-rex find could bring jurassic park to life
David Adam, science correspondent
Friday March 25, 2005
The Guardian

Scientists have raised the spectre of a "Jurassic Park" resurrection of dinosaurs after extracting what looks like blood vessels and intact cells from a Tyrannosaurus rex.

Tests on the 70m-year-old samples continue, but the US scientists have not ruled out the possibility of extracting DNA - the starting point for the cloning of dinosaurs in Michael Crichton's bestseller, which was the basis for Steven Spielberg's hit film.

The well-preserved fossil skeleton of the T-rex was unearthed in 2003 from Hell Creek, Montana, in the US. When the researchers analysed one of its thigh bones, broken during its recovery, they found a flexible, stretchy material threaded with what appeared to be transparent and hollow blood vessels. The vessels branched like real blood vessels, and some held cell-like structures.

Mary Schweitzer, from North Carolina State University, in Raleigh, who led the team, told the journal Science: "It was totally shocking. I didn't believe it until we'd done it 17 times."

The vessels closely resembled those from the bones of present-day ostriches, the scientists said. Many contained red and brown structures that looked like cells. Within those, the team discovered smaller objects similar in size to the nuclei of blood cells in modern birds.

"The vessels and contents are similar in all respects to blood vessels recovered from extant ostrich bone," the researchers report in Science.

Their next step is to determine the soft tissue found inside the bone; it might be original T-rex material. However, it could be that the proteins have been replaced by other chemicals over the centuries.

Scientists have previously recovered intact cells trapped in 225m-year-old amber, only to find the nuclei had been replaced with resin compounds.

Dr Schweitzer's group said they had identified some protein fragments that still responded to tests.

Other experts were hopeful. In the UK, David Martill, a biochemist at the University of Portsmouth, said: "There's a reasonable chance that there may be intact proteins." He speculated that it might even be possible to extract DNA.

Lawrence Witmer, a palaeontologist at Ohio University's college of osteopathic medicine, agreed: "If we have tissues that are not fossilised, then we can potentially extract DNA. It's very exciting."

If the cells do contain original biological material, the scientists would be able to investigate everything from dinosaur physiology to how the creatures evolved into birds.

Cloning a T-rex would be far more difficult. Current techniques need hundreds of nuclei from living cells, said Duane Kraemer, a cloning expert at Texas A&M University, who leads a project called Noah's Ark, which stores tissue samples from animals facing extinction. Any dinosaur DNA remaining in the cells would probably be damaged or degraded, making it impossible to use for cloning .

In the fictional Jurassic Park, scientists repaired damage using amphibian DNA. In reality, they would need to know the complete dinosaur genome. "To determine what has been damaged you need to know what the original DNA sequence was," said Dr Kraemer.

Alex Greenwood, a molecular biologist at the American Museum of Natural History, in New York, has compared trying to clone an extinct animal from damaged DNA to throwing all the parts needed to make a car down the stairs of a building in the hope that a Porsche 911 will emerge.

This has not stopped people trying, and several groups have made unsuccessful attempts to resurrect the woolly mammoth using genetic material recovered from a preserved carcass.
» Quantitative Genetics Issue of Heredity
March's Heredity issue is a focus on quantitative genetics. The issue contains a collection of articles that cover the range of quantitative genetics, and includes some new methods for calculating IBDs and inferring parental genotypes. If you are unfamiliar with how quantitative genetics and QTLs are used in current evolutionary biology research, this issue should be informative and worth a look.

http://www.nature.com/hdy/journal/v94/n3/index.html
» "The Evolution of the Genome" - New book
I just received my copy of T. Ryan Gregory's new book "The Evolution of the Genome." After an initial skimming of the chapters, it looks like the book will provide a current overview of large scale genome evolution issues, especially genome size (Gregory's major reseach focus). I will post a mini-review once I read it (which could be quite some time from now).

More info can be found at:
http://www.genomesize.com/rgregory/book/
Top of Page Powered by LiveJournal.com