Genética humana

El objetivo de este tema es describir lo que es la genética, como rama científica que trata los genes humanos y estudiar su evolución en los últimos años ya que se han sido relaizando descubrimientos muy interesantes y que suponen la aplicación de una serie de complejas técnicas bioquimicas, de matemáticas, de biologia molecular, etc.
En el caso particular del estudio de restos humanos y momias, gracias al ADN se han podido determinar bastantes datos, pero eso lo dejamos para más adelante y ahora vamos a intentar comprender que es el ADN.

La palabra genética tiene su origen etimológico en la palabra griega γένος , gen, que significa descendencia. Ya antes de conocer la estructura del ADN se habia elaborado un modelo de transmisión, ya que las similitudes que existian entre padres e hijos era algo que estaba manifiesto al observar a personas perrtenecientes a una familia.


Los genes

He encontrado esta imagen en wikipedia que puede ilustrar la explicación de lo que es un gen




En la imagen anterior explican lo siguiente sobre la misma:
Diagrama esquemático de un gen corto, dentro de la estructura en doble hélice de ADN que al comprimirse va formando un cromosoma (derecha). Se trata de un gen eucariota (el procariota carece de intrones). Las proteínas se codifican sólo en los exones.

Un gen puede definirse como la unidad básica de la herencia donde está contenida la información básica, es una secuencia lineal y organizada de nucleótidos de ADN, con la información básica para la consecución de la síntesis de una macromolécula, por ejemplo la proteina, Art ,etc.
Antes de seguir hablando sobre los genes, cuelgo esta imagen, que es bastante instructiva:


fuente imagen www.ornl.gov/sci


Antes de saber su estructura, se pensaba en que estuvieran constituidos por algo realmente extraño al resto de las células pero con las investigaciones se comprobó que los elementos constitutivos eran de lo más común ya que en estos elemenytos tenemos el Oxigeno, hidrógeno, nitrógeno, fósforo y por supuesto, el carbono.
Sobre la palabra "gen", que ya vimos su etimologia, debemos destacar lo siguiente:
Fue Wilhelm Ludwig Johannsen quien en e año 19o9 se refiere a la unidad física y fundamental de "herencia biológica".
En el año 1950 es cuano re hace "impone" el término de gen , concebido como la cadena de ADN que dirige la síntesis de una proteína. El gen es pues un codificador de proteínas y debe tener una estructura definida por el orden lineal de sus tripletes o codones.

Recordemos que James Watson junto con F.H. Crick recibieron el premio nobel en el año 1962 por su descubrimiento de la estructura de los genes.
Con anterioridad hay que destacar a Mendel, que fue quien propuso la idea de la existencia de los genes y que llamo "factores".

Algunos genes codifican más de un polipéptido y que una proteína puede ser codificada por el conjunto de diferentes genes.

El gen es una molécula helicoidal larga formada de dos tiras de ácido desoxirribonucleico (DNA) con peso molecular generalmente del orden de varios millones. Un segmento muy corto de tal molécula se presenta en la figura siguiente. Esta molécula está compuesta de varios productos químicos simnples dispuestos en forma específica, diferente para cada tipo de gen. (GUYTON: 30)




En la imagen podéis ver la estructura de una célula de ácido desoxirribonucleico. Esas zonas que se ven en el centro son las bases púricas y pirimídicas que forman la clave de un gen.

Hemos comentado que un gen está compuesto de varios productos químicos, veamos ahora que tipo de componentes son.

Comenzamos por los soportes externos de la escalerita: que estan compuestos por moléculas del azúcar deoxirribosa, de formal alternada con enlaces de fosfato (ácido fosfórico, Y las bases quedaan entre las tiras y las conectan entre sí. Los peldaños en esa escalerita estan formadas por dos bases apareadas:

Un par formado por adenina y timina : A y T
otro par pormado por citosina y guanina : C y G

Atención a una cosa muy importante: El órden en el que se hallan las bases en la molécula es lo que establece su función genética.

aquí para que se vea mejr, cuelgo una foto de Winchester



Podeis apreciar una pequeñísima porción de un gen mientras se replica.

El gen se abre por las bases que constituyen cada una de las mitades, y estas mitades atraen hacia sí las partes que les faltan.
Esta es la manera de "formarse", a partir de uno, los genes idénticos.

Los genes deben ser capaces de realizar copias de si mismos que sean exáctas, esto es fundamental porque es el proceso por el cual se produce la reproducción. El proceso de duplicación se llama "replicación".

Cuando se produce la reproducción, los genes lo que haces es comenzar a escindirse a partir del centro. Una similitud importante para comprender esto es compararlo a como se abre una cremallera.

Los genes tienen emarejadas las bases mediante unas uniones de hidrogeno, bueno pues al dividirse, es decir separarse como en el ejemplo de la cremallera, cada gen se divide en dos partes pero al estar partido está iincompleto y lo que hace es atraer partes iguales a las perdidas para así poder ser un gen completo otra vez. Y pasa lo siguiente:

La adenina atrae a la timina
la timina atrae a la adenina
la citosina atrae a la guanina y
la guanina atrae a la citosina.

Y así se produce la duplicación de los genes.



Anteriormente salió una palabra que creo que merece la pena definir, es el concepto de " codominante" y significa lo siguiente:
Dos genes alelos son condomitantes cuando ambos se expresan completamente en el individuo heterócigótico. Ejemplo: los alelos de los antígenps A y B de la sangre (Winchester 207)

Los genes pueden controlar la formación de otras substancias en la célula, mediante el código genético.
Las palabras de código consisten en tripletos de bases, es decir tres bases constituyen una palabra.
Algunas palabras del código no hacen que los aminoácidos se incorporen a las proteinas, pueden efectuar otras funciones en la síntesis de las moléculas proteínicas.
Las palabras de código se denominan "palabras sin sentido" porque así las llamaron los primeros investigadores, pero ahora sabemps que una tira sola de ADN puede representar varios genes diferentes y con cada par de genes sucesivos separado por una palabra de código "sin sentido".

Los genes actuan a través de las proteinas y esas proteinas se forman en los ribosomas del citoplasma, ensamblando aminoácidos.

Desde el gen se envian mensajes que toman la forma ARN mensajero formado por los genes y pasa a los ribosomas.

El ARN -m , (lo de la m es por lo de mensajero) consta de dos partes que son similares a las de los genes pero la diferencia está en que
-tiene una sola cadena, y recordemos que en los genes hay dos cadenas
-el azucar de los genes es aquí ribosa
-una de sus bases es uracilo y recordemos que en los genes era de timina.

imagen de wikipedia :
fases deñ ARN -mensajero

Ahora tenemos un ejemplo para comprender lo que pasa cuando de ingieren proteinas: Al injerir un filete de ternera, este se descompone en sua aminoácidos cuando está en el intestino. Dentro de cada célula, los aminoácidos se reagrupan en proteinas, según los mensajes que le dan los genes. Como es lógico los genes que se comen son de vaca, pero los aminoácidos que contienen se agrupan según los genes humanos y forman así proteinas humanas.


Cada persona es única y hay tantas clases de genes que no se dan dos personas que tengan la misma combinación por lo que no se producen las mismas clases de proteinas celulares, excepto claro está ,la de los gemelos idénticos.
Veamos como se producen las caracteristicas de la célula para que se formen gemelos :

A partir de una misma célula, se produce una división en dos partes que son idénticas.
Entre hermanos, en general, existen más genes en común que entre los hijos de padres diferentes, al igual que dentro de los grupos raciales, los inividuos compartes una serie de caractersticas que son comunes.
Para recibir el transplante de un organo, este debe realizarse entre personas compatibles, es decir, el cuerpo produce una serie de anticuerpos que reaccionan contra cualquier elemento extraño que sea diferente, es decir contra cualquier proteina extraña, por eso en el caso de transplantados , los emdicos tienen que hacer un tratamiento específico para que no se productan esos anticuerpos, pero curisamente, en el caso de genélos idénticos en el que se transplanta ur órgano de uno a otro, ese tratamiento no haria falta.

Letter from Ireland: Mystery of the Fulacht Fiadh

Volume 65 Number 1, January/February 2012 by Erin Mullally
Versions of the same Bronze Age structure pop up all around Ireland and throughout the United Kingdom. Archaeologists, however, still have not agreed on their purpose.


Emer Dennehy)

On a typically misty morning in the west of Ireland, just outside the medieval town of Athenry, County Galway, archaeologist Declan Moore opens the trunk of his car and invites me to pull on a pair of Wellingtons. “Believe me, you’ll need them,” he assures me as we cross the parking lot and hop a fence into a nearby field.

Moore is taking me to visit an unexcavated fulacht fiadh (pronounced FULL-ahk FEE-add), or fulachtaí fia in plural, the most common type of prehistoric archaeological site in Ireland. Better known as a “burnt mound” in the neighboring United Kingdom, where they are also found, there are nearly 6,000 recorded fulacht fiadh sites dotted around Ireland alone. As we trudge through the wet and soggy field, Moore points out a small stream. “They are usually found near water or in marshy areas, so this is a prime location,” he explains.

When we arrive at the site, Moore shows me the basic features of a fulacht fiadh—a horseshoe-shaped mound of soil and rocks surrounding a depression big enough to park a small car in. Moore climbs the four-and-a-half-foot mound and quickly wipes away some of the soil to expose the layer of stones. He then points to the depression. “If we were to excavate, we’d find a trough dug into the ground there,” he says. It takes us only 15 minutes to fully explore the still-buried site.

Although commonplace and easy to identify, the fulacht fiadh remains enigmatic. There is no consensus among archaeologists about what they were primarily used for. Various theories—such as cooking, textile production, bathing, and Moore’s personal hypothesis, a type of ancient microbrewery—have all been proposed. But a lack of consistent artifacts associated with any of these activities at excavated fulacht fiadh sites continues to shroud the purpose of the burnt mounds in mystery.

Fulacht fiadh sites typically date to the Middle Bronze Age (1800 B.C.). The structures are usually found alone, but have also appeared in groups of two to six, spaced as close as 16 or so feet from one another, making an archaeological complex. “Most fulacht fiadh sites are somewhat isolated, with only a few having been found as part of a permanent settlement,” says Emer Dennehy, an Irish archaeologist with the Railway Procurement Agency in Dublin who studies the fulacht fiadh. “We’re still unsure if this indicates a seasonal use with hunting expeditions or if they were used on a regular basis in conjunction with permanent settlements located elsewhere. It was convenient to locate these sites close to wet and damp areas, which would not have been suitable for habitation.”

Choosing wetland areas as locations allowed for the characteristic troughs found at the center of these sites to be self-filling, either because they were situated below the water table or because they were built directly above a spring. Though they can differ in size and shape, most troughs are roughly rectangular in outline and average five feet in length, four feet in width, and two feet in depth. Most troughs that have been excavated are unlined, but roughly 30 percent are lined with clay, wood, or stone slabs.

Surrounding the troughs are U-shaped mounds made of stones. These mounds can reach heights of more than six and a half feet, though on average they are roughly three feet high, and made of sandstone or limestone. Neither rock type is typically found close to fulacht fiadh sites, indicating that the Bronze Age Irish chose the stones deliberately.

According to Dennehy, the mounds likely cover hearths where the stones, which show evidence of heat-cracking, were fired. The cracking also provides strong evidence that after being heated, the rocks would be placed in the troughs to heat water. “The stones that were heated and shattered during this process were discarded nearby,” Dennehy explains, “gradually accumulating to form the mound surrounding the trough.”

The water in the trough could have been brought to a boil by adding fired stones, says Dennehy. Demonstrations on modern-day re-creations of fulachtaí fia have shown that intermittently adding one heated rock can keep a steady boil. “You can be absolutely sure it was used for boiling water,” says John Waddell, an emeritus professor of archaeology at the National University of Ireland, Galway. “It’s the one certain thing about the fulacht fiadh.”

In Gaelic, “fulacht” means “cavity,” though as interpreted through Irish literature it can mean cooking site. “Fiadh” means “wild deer.” While that translation lends support to the structure’s use as a cooking site, many archaeologists believe the term is inaccurate. Waddell, for instance, supports calling them burnt mounds, as they do in the United Kingdom.

Until recently, the conventional wisdom has been that the fulacht fiadh was used for cooking. Michael J. O’Kelly, a professor of archaeology at University College Cork, examined fulacht fiadh sites in southwestern Ireland in the 1950s, conducting several experiments. Among them was adding animal meat to boiling water in a reconstructed fulacht fiadh.

The cooking demonstrations, while lengthy (a single leg of mutton took nearly four hours to cook), prompted the concept of the fulacht fiadh as a cooking site to pass into accepted archaeological theory. But bones and other animal remains are not consistently found near fulachtaí fia, which would be surprising for locations where meat would have been regularly boiled. Some archaeologists also suggest the Bronze Age Irish would have preferred to roast meat over an open hearth, which would have been simpler and more efficient, and would also have resulted in a tastier meal.

Another possible use for the fulacht fiadh might have been textile production. “We know that dyeing was practiced in Britain and Northern Europe at a very early date,” writes Anne-Marie Denvir in her undergraduate dissertation on the fulacht fiadh for Queen’s University Belfast in Northern Ireland. Denvir constructed a replica fulacht fiadh in which she dyed a sheep’s fleece green using crushed ivy berries. She also washed a fleece using stale urine and did an experiment involving “fulling” (thickening fabric by heat-shrinking it). As with cooking, though, there is little archaeological evidence in the form of artifacts to support textile production.

Several other excavated fulacht fiadh sites suggest that they may have been used as ancient saunas or sweathouses. Though very rare, these few sites include the remains of possible structures that would have been built over the troughs in order to capture any escaping steam. Similarly, the fulacht fiadh could have been used for bathing purposes, but that idea also faces a
lack of evidence.

One of the interesting facets of the fulacht fiadh debate is the role that experimental archaeology can play in investigating the mystery they present, as evidenced by O’Kelly’s and Denvir’s proof-of-principle demonstrations. Declan Moore and fellow archaeologist Billy Quinn are the latest to test a fulacht fiadh theory in practice.

One morning in 2003, before continuing work on excavating a fulacht fiadh in County Galway, a hungover Quinn reflected on his condition and had an insight: Perhaps the mysterious Irish archaeological structure was used as an ancient brewing site.

Historical evidence suggested it was a possibility. Residue analysis from 9,000-year-old pottery found in northern China indicated the vessels once held a fermented drink of fruit, honey, and rice. And evidence for beer drinking in the Middle East begins to appear around 4000 B.C. and includes a recipe carved on a Sumerian tablet dating to 1800 B.C. for brewing in a pit. It’s not inconceivable that brewing was also taking place at the same time in Bronze Age Europe.

“Brewing at Irish monasteries [dating back to the late fifth century A.D.] was renowned for its time. The knowledge that these monks had about brewing had to have come from an earlier tradition,” remarks Moore. “The fulacht fiadh could represent the point at which man started popular brewing efforts in Ireland.”

After visiting breweries in northern Scotland, Belgium, and Germany to learn ancient techniques and more modern “hot-rock brewing,” Moore and Quinn decided to make their own fulacht fiadh brew in August 2007. They buried a wooden cattle trough that was about five and a half feet long and a little over two feet wide and deep, in Quinn’s backyard. They filled it with water and heated it to just under 153 degrees Fahrenheit, as advised by brewers they’d consulted
using stones fired in a hearth about 15 feet away.
At its simplest, beer consists of malted grain, water, and yeast. Using malted barley donated by a local brewer, they stirred it into the hot water. After 45 minutes, the grains were converted to a sugar syrup called wort, which was transferred into special replicas of Bronze Age pots. Yeast was then added, as were elderflower, juniper berries, and yarrow for flavoring, and the brew was left to ferment for three days. (Moore and Quinn note that windblown yeast would have triggered natural fermentation for Bronze Age brewers.)

Moore and Quinn converted nearly 80 gallons of water into 30 gallons of ale that was copper in color and had a smoky flavor. Not much like beers we drink today, the concoction was closer to a “gruit” ale, a reference to herbs used to give beer its bitter taste before brewers turned to hops.

When Moore and Quinn first published the results of their foray into experimental archaeology in the magazine Archaeology Ireland, several archaeologists, as well as home brewers, voiced their support for the work. Members of the Irish Archaeobotany Discussion Group, however, expressed doubt in Moore and Quinn’s theory, again pointing to a lack of accompanying evidence at fulacht fiadh sites. “Such large-scale processing of cereals would leave a regular trace in the archaeological record, perhaps in the form of uncharred, malted grains at waterlogged sites,” the group wrote in a letter responding to the Archaeology Ireland article.

Moore and Quinn counter that grain used during the brewing process could have been used as animal feed. The pair also point to the discovery of grinding stones at fulacht fiadh sites in both Ireland and the United Kingdom, as well as confirmed findings of traces of cereal grain and wheat near a Bronze Age wooden trough at a site in Wales in 2009, as further evidence to support their theory.

Ultimately, pottery evidence might be required for Moore and Quinn to prove their brewing hypothesis. Vessels used for fermentation would have calcium oxalate residue left behind as wort turned alcoholic. Unfortunately, a lot of pottery investigated from the area has been exposed to the elements, says Patrick McGovern, an archaeologist at the University of Pennsylvania who specializes in ancient alcoholic drinks. “I certainly believe that the peoples of Ireland were brewing beer or perhaps a mixed extreme beverage,” he explains. “But not enough samples have been tested to give us a definitive answer.”

Regardless of whether his and Moore’s theory is one day proved, Quinn says the Bronze Age brewing experiment revived discussion over the uses of fulachtaí fia. While the mystery of the burnt mounds will continue, at least for the foreseeable future, in time archaeologists may move toward a consensus that the fulacht fiadh was used in a variety of ways during the Bronze Age, brewing among them.

Quinn, in fact, believes that’s likely the case. “Overall the fulacht fiadh may have indeed been multifunctional, something like our modern kitchen sink—used for many different purposes.”

Dennehy notes that constructing a fulacht fiadh was clearly a planned and time-intensive undertaking. “The communities of the time felt a need to construct them over and over again,” she says. “Bronze Age people had a strong knowledge of their environment, and it probably does them a disservice to consider the fulacht fiadh as simply a run-of-the mill cooking site.”

Erin Mullally is an American freelance writer based in Dublin.

http://www.archaeology.org/1201/letter/fulacht_fiadh_ale_bronze_age_ireland.html

Love Pipe Unearthed in Israel

Image: The pipe mouthpiece. (Credit: Clara Amit, courtesy of the Israel Antiquities Authority).

A centuries-old mouthpiece of a pipe, which might have been used to smoke hashish, has been unearthed in the Jewish Quarter of Jerusalem, according to the Israel Antiquities Authority.

Bearing the Arabic inscription "love is language for the lovers," (literally translated, it reads "heart is language for the lover") the clay pipe was likely intended as a gift between lovers.

According to Shahar Puni, of the Israel Antiquities Authority, the object dates from the 16th to the 19th century, when Jerusalem was part of the Ottoman Empire, a Turkish state that stretched from southeastern Europe, across northern Africa and through most of the Middle East.

BLOG: Earliest Beehives Discovered in Ancient Israel

"Clay pipes of this kind were very common in the Ottoman period, and were mostly used for smoking tobacco, and some were even used to smoke hashish," Puni said in a statement.

"The Ottoman authorities tried to combat this practice but failed when it became clear that smoking was firmly entrenched in all levels of society," Puni said.

Smoking was popular amongst both men and women, and was often done in cafes and in groups of friends.

Indeed, 19th century drawings show Jerusalemite women smoking clay pipes similar to the one unearthed in the Jewish Quarter.

"Pipes were also used as a piece of jewelry that could be worn on a garment," Puni said.
http://news.discovery.com/history/love-pipe-unearthed-111230.html

Arkesilas

The Cyrenian king Arkesilas watching over the bundling of wool (Boardman) or the preparation of silphion. Tondo of a Laconian black-figure cup, 565–560 BC. From Vulci, Etruria.

Archaeologists Excavate Legendary City of Danhttp://popular-archaeology.com/issue/december-2011/article/archaeologists-excavate-legendary-city-of-dan

The monumental Biblical city is yielding more of its secrets to archaeologists.

Looking at the remains today, it is difficult to believe that only a fraction of this monumental ancient site has been uncovered. Yet it has far and away yielded some of the most impressive discoveries of Near Eastern, or Levantine, archaeology. Here, according to the Biblical account, ancient Israel established one of its great temples. And here, late Neolithic people first settled as early as 4500 B.C.E., and Bronze Age inhabitants constructed the world’s oldest known gated archway.

Known today as Tell el-Qadi, more popularly as "Tel Dan", the site is located near Mount Hermon in Northern Israel adjacent to one of the sources of the Jordan River. The 'Tel', or mound, was defined very early on during the Middle Bronze period when massive defensive ramparts were constructed, encircling the city. Although the ramparts rise about 20 meters from the surrounding surface area, the interior of the site is actually as much as 10 meters lower than the tops of the ramparts. It was first identified based on historical records as the city of Laish, a town allied with the Phoenician Sidonians and later renamed "Dan" after the early Isrealite tribe of Dan, which conquered and settled it as documented in the Book of Judges. Thanks to a bilingual Greek and Aramaic inscription found at the site in 1976, this city name has been confirmed. Translated, that inscription reads, “To the God who is in Dan, Zoilos made a vow.” Ancient Egyptian texts and cuneiform tablets from Mesopotamia document Dan’s significance during the second millennium B.C.E. Later, during the Iron Age, Aramaeans, Israelites, and Assyrians fought over this city. Dan was a recognized cultic center even into the Greco-Roman period.

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Section of rampart at Tel Dan. Ani Nimi, Wikimedia Commons

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Although the site was first identified by Edward Robinson in 1838, the best known excavations of the site began in 1966 under the late Israeli archaeologist Avraham Biran, and it was under his direction that the most spectacular discoveries were made. His team of excavators uncovered a mud-brick city gate (pictured right) dated to around 1750 BCE (the Middle Bronze period), the time of the Biblical patriarchs. It is popularly known as Abraham's gate because, according to the Biblical account, Abraham journeyed to Dan to rescue his nephew Lot. They also uncovered an Israelite temple, thought by Biblical scholars to be the temple built by Jeroboam, King of Israel after the United Monarchy split into Israel in the north and Judah to the south. It was this temple where, according to the Bible, he housed the golden calf and challenged the temple in Jerusalem as a religious center of Israel. Additionally, an elaborate Israelite gate was discovered, consisting of an upper gate and a lower gate, each featuring inner and outer gates and plazas. Arguably the most sensational find, however, was the discovery of parts of a basalt stone stele bearing an inscription containing a declaration by a king of Damascus (possibly Hazael, c. 840 BCE, or Ben-Hadad, c. 802 BCE). Translated, it proclaims his military victory and destruction of at least some parts of the Kingdom of Israel, and the killing of two kings of Israel. Notably, it contains the phrase "House of David" ["......and I killed [Ahaz]iahu son of [Jehoram kin]g of the House of David"], a phrase rarely, if at all, seen in any extra-biblical context. Today, many Levantine archaeologists and scholars agree that it refers to a royal dynasty of David and that the Tel Dan Stele therefore represents tangible evidence that there was indeed a "kingdom", or royal dynasty, of David. (See more photos of Tel Dan below)

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Plaza of the outer gate of the Iron Age II Israelite gate complex, looking toward the gate. Photo credit: Ronald A. Simkins and the Virtual World Project

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Chamber in the upper gate of the Israelite gate complex. Photo credit: Ronald A. Simkins and Virtual World Project

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Stone altar in a side room of the Iron Age II upper gate complex. Photo credit: Ronald A. Simkins and the Virtual World Project

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View of the monumental stairway to the temple platform. Photo credit: Ronald A. Simkins and the Virtual World Project

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Monumental steps to the temple platform. Photo credit: Ronald A. Simkins and Virtual World Project

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http://popular-archaeology.com/issue/december-2011/article/archaeologists-excavate-legendary-city-of-dan

2,000-year-old relief bust found in Stratonikeia

TODAY'S ZAMAN, İSTANBUL

A 2,000-year-old relief bust of a king was discovered during excavations in ancient Stratonikeia in Muğla's Yatağan district.


Dr. Bilal Söğüt, a professor of archeology at Pamukkale University and head of the excavations, told the Anatolia news agency that they found a street in the ancient city which began with a gate and was lined with columns. During their excavations, they also discovered the bust of a king dating back to the Hellenistic period. The bust, which is one-and-a-half meters tall and nearly two meters wide, features depictions of bull heads and the figure of a goddess, Söğüt said.

“The depictions of bull heads on the bust represent wealth and power. It was in this region that we previously found a racing chariot. The discovery of 1,500-year-old mosaics here was another welcome breakthrough for us,” he said.

According to Söğüt, the city walls constitute an important part of the excavation work carried out in the ancient city. “The city walls were restored approximately 2,400 years ago by King Mausolus. We have begun excavating these 2,400-year-old walls of this ancient city. Upon the completion of the excavations, we will start work on restoring the area,” he said.

Söğüt said he thinks the walls surrounding the ancient city are nearly 3,600 meters long. “We discovered that one 400-meter section of wall has been preserved to this day. After completing restoration, we will open the wall to visitors," Söğüt said.

A 100-person team of academics, field workers and students discovered 460 artifacts in the ancient city in the seven-month-long excavations that took place last year, according to Söğüt. The artifacts were delivered to the Muğla Museum. The pieces date back to the Roman and Byzantine periods, he said.
http://www.todayszaman.com/news-267387-2000-year-old-relief-bust-found-in-stratonikeia.html

Viewpoint: Has 'one species' idea been put to bed?

Here, Prof Clive Finlayson looks back at the year's developments in human evolution research and asks whether recent discoveries rule out a well known idea about our ancestors.

Hobbits on Flores, Denisovans in Siberia, Neanderthals across Eurasia and our very own ancestors.

Given this array of human diversity in the Late Pleistocene, we might well be forgiven for thinking that Ernst Mayr's contention that "in spite of much geographical variation, never more than one species of man existed on Earth at any one time" had finally been put to bed.

It now seems that a high degree of diversity was also present in the Middle Pleistocene, revealed in the latest analysis of human teeth from that period.

Mayr, one of the great evolutionary biologists of modern times, proposed his single species idea in a Cold Spring Harbor Symposium, published in 1950.

The idea of a single species of human has received a great deal of criticism since Mayr's day but it has also had its vociferous advocates.

So, can we really conclude that the concept was fundamentally flawed on the basis of all the new - fossil and genetic - evidence? That depends on how we understand and define species.

Harvard biologist Ernst Mayr's concept had some vociferous advocates

For biologists, like Mayr, species are entities composed of individuals that, in the wild, reproduce among themselves but not with other species.

But palaeontologists use other definitions of species and these have allowed them to classify fossils that cannot be otherwise categorised on the basis of Mayr's biological species concept.

What the palaeontologists call species are essentially divergent lineages but we cannot know whether these had reached levels of genetic independence or not.

Mayr recognised that there had been "much geographical variation" in humans but he just did not think that such variation had led to new species. So the apparently polarised positions are not really that far apart. Enter genetics.

The Neanderthals have long been the "controls" in the human experiment; those we have chosen to compare and, mainly, contrast with the human model. Drawing distinctions between "them" and us has helped in creating a sense of the uniqueness of our condition and it has been natural that we should regard them as a different species.

The species living at Denisova Cave awaits scientific nomenclature

But now we know that Neanderthals and our ancestors exchanged genes so, using the biological species definition, they must have been the same species. But they had diverged for over half-a-million years: they were distinct lineages which would make them distinct palaeontological species.

And it seems they were not the only ones to exchange genes with our ancestors. The enigmatic Denisovans (still awaiting scientific nomenclature) also exchanged genes with some of our ancestors and they ranged widely.

So the paradox "one species-many species" depends very much on perspective and there is little, it would seem, that contradicts Mayr's contention of geographical variation in a single biological species.

While all this has been happening, more and more papers are being published that are breaking down the differences between Neanderthals and our ancestors.

Now it seems that Neanderthals beach-combed for molluscs as far back as our own ancestors did (around 150 thousand years ago along the Mediterranean coast of Spain), so a defining feature of our modernity and geographical expansion has been eroded.

Stalwarts have been left with our superior cognition, expressed via symbolism, as the last bastion that separates us from the Neanderthals. But even here recent papers suggest that Neanderthals used coloured pigments and may have even worn raptor feathers!

The historical downgrading of our Neanderthal cousins has gone well beyond the scientific. Neanderthals still remain, in many people's minds, the archetypal brutes. But this popular view is gradually changing as scientists are recognising the need to put new ideas across to a wider public.

A meeting in the Neander Museum, near Dusseldorf in Germany, last October brought together scientists and managers from across Europe in an effort to create a network of sites and museums that tell the story of humans in the Pleistocene of Europe.

The Neander site gave its name to their human namesakes but an earlier skull had been found, in 1848, in Gibraltar and went unrecognised.

A network of museums could tell the story of ancient humans in Europe

Work in Gibraltar, the last known place where Neanderthals survived, has changed our understanding of Neanderthal ecology and a key site on the Rock - Gorham's Cave - has now been included in the United Kingdom's Tentative List for World Heritage nomination.

It is recognition that the human evolution story, and the Neanderthals, are very much part of our global heritage. Gibraltar plans to do more as it pioneers the combination of research with public access.

The recently elected Government included in its manifesto a commitment to commemorate the site of the 1848 discovery and there are also plans to develop a unique thematic "Neanderthal Park", the first of its kind in the world.

And a major conference is planned for September next year when experts from all over the world will meet in Gibraltar to revise our ideas about "the human niche". After decades of bad press we are finally getting round to humanizing the enigmatic Neanderthals.

http://www.bbc.co.uk/news/science-environment-16339313

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