Easenglish

 

neanderthals and the modern humans

Passage

Start Timer

A. Without the ability to examine human species that have not attained similar things, it is difficult to determine the evolutionary processes that have separated modern humans from other animals. However, Svante Paabo and his colleagues from the Leipzig-based Max Planck Institute for Evolutionary Anthropology have created a scientific masterpiece that makes it possible for such a comparison. They made a genome analysis of Neanderthal man public in 2009 at an American Association for the Advancement of Science meeting. 

B. Between 400,000 and 30,000 years ago, Homo neanderthalensis, to use its correct name, lived in Europe and some regions of Asia. At the end of this time, Homo sapiens, who were migrating from Africa, invaded its territory and coexisted with it. The two species, however, were unable to establish a long-term cohabitation. Neanderthals always vanished in a region shortly after Homo sapiens arrived there, for reasons that are still unknown.

C. Prior to 2009, Dr. Paabo and his group had only superficially compared the DNA of Neanderthals and contemporary humans. They have since conducted a more in-depth study, which has helped to illuminate the two species' intertwined history in an intriguing way. It turns out that history is more interconnected than many people initially thought.

D. Dr. Paabo and his colleagues compared the genomes of five living people from different regions of Africa and Eurasia with their Neanderthal genome, which had been painstakingly reconstructed from three bone samples found in a cave in Croatia. There was no evidence of interbreeding between Neanderthals and modern humans in earlier genetic studies, which only looked at DNA passed from mother to child in cellular structures called mitochondria. This conclusion is incorrect, according to a newer, more thorough investigation that looks at DNA in the cell nucleus rather than the mitochondria. Dr. Paabo has demonstrated that between one and four percent of Eurasians are Neanderthals by comparing the DNA in the cell nuclei of various Eurasians and Africans, whose ancestors could have interbred with Neanderthals but did not because of their lack of overlap.

E. That's interesting. It demonstrates that the two species were inter-fertile despite living many hundred thousand years apart. However, it is puzzling that no Neanderthal mitochondrial DNA has been discovered in modern humans. Historically, invasions typically followed a pattern where the invaders' males mated with the invaded females. So, one thing to know about oneself, at least for non-Africans, is that they have a little Neanderthal in them. But Dr. Paabo's research also sheds light on how different the species are. Modern humans, Neanderthals, and chimpanzees can be used to compare genetic changes that several species of humans have shared as they have evolved away from the great ape lineage from those that are specific to Homo sapiens.

F. Neanderthals share more than 90% of the "human accelerated regions" [3] that have been found in modern humans. The others are not, though. Since the species split, 212 regions of the genome have apparently undergone significant evolution, according to Dr. Paabo. It is frequently unclear what a specific piece of DNA is actually doing because genome science is still in an extremely early stage. However, a closer look at the 20 largest DNA regions that have changed in this way reveals that they contain a number of genes linked to cognition and whose dysfunction can result in severe mental health issues. Therefore, it appears that the search for the essence of modern humanity should begin with these genes.

G. Another gene called RUNX2, which regulates bone growth, is also present in the recently evolved DNA regions. That could explain why the two species' rib cages and skulls differ in appearance. In contrast, a previous stage of the research had already demonstrated that Neanderthals and modern humans share the same variation of the FOXP2 gene, which is involved in speech and differs in chimpanzees. So everything looks very promising and represents Dr. Paabo's second quick success. Using mitochondrial DNA from a little-finger bone, one of his teams has proven the existence of a previously unknown species of humans. Humanity would be able to learn more about itself if that species' genome could also be fully read.

Questions 27-29

Complete the summary below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
The nature of modern humans:
Recent work in the field of evolutionary anthropology has made it possible to compare modern humans with other related species. Genetic analysis resulted in several new findings. First, despite the gap in time between the evolution of Homo sapiens and Homo Neanderthalensis, 27.________ did occur. Second, genes that emerged after modern humans diverged from Neanderthals are linked to intelligence and skeletal 28.________. When examination of a 29.__________ resulted in the identification of a new human species, the potential for this field of study to shed light on the nature of modern humans was strengthened.

Questions 30-34

Look at the following characteristics (Questions 30-34) and the list of species below.

Match each feature with the correct species, A, B or C.

Write the correct letter, A, B or C.

NB You may use any letter more than once.

30.  Lived in Europe and Asia in the past.

31.  Originated in Africa.

32.  Did not last long after immigrants arrived.

33.  Mated with a different species.

34.  Appears to have prevented another species from receiving mitochondrial DNA.

List of species
A Homo neanderthalensis
B Homo sapiens
C both Homo neanderthalensis and Homo sapiens

---