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英国essay代写 Did Neanderthals and modern humans interbreed

事实上,现代人的DNA是一些比例的尼安德特人DNA相关引发了关于是否事实是真实的或伪造的一个非常严肃的辩论。研究表明,大约有百分之四的遗传化妆谁不追溯至非洲现代人类相似的尼安德特人。考虑到一个事实,一个正常的人类的DNA变化只有百分之二与黑猩猩的事实上,这场辩论是值得有。

根据一些资料来源,测序人类DNA的过程不是一个确定的过程。据说人类化石中所含的DNA被污染,有时没有足够的足够进行足够的基因比较。然而,在莱比锡的马克斯普朗克研究所,德国在现代技术的帮助下成功的DNA序列的尼安德特人与现代人类的DNA进行比较。即使机器使用和使用的方法被称为不完美,他们设法破译尼安德特人DNA三分之二和想出的统计,百分之四的现代人的DNA是相似的人。然而,该研究并没有指出任何人的特性,可以直接归因于尼安德特人,有研究表明现代人的头盖骨的发展过程可以被归因于尼安德特人但没有事实支持这一理论(Trinkaus 2007)。对近代早期欧洲的人的特征与尼安德特人使用已记录的古生物资料显示有现代欧洲早期人类和尼安德特人之间的相似特征的比较(Trinkaus 2007)。然而同样的相似性不追溯到旧石器时代中期的现代人类(mpmhs)从他们的早期欧洲现代人据称来自(Trinkaus 2007)。这意味着,必须要有来自非洲的欧洲早期现代人类的迁移过程中被遗传交换(Trinkaus 2007)。

从上面我们看到,关于现代人和尼安德特人之间的遗传关系的事实尚不清楚这一点。这证明有些研究是因为足够的考古学证据和科学事实的缺乏;因此我们仍然面临的问题是,尼安德特人和现代人类杂交?这个问题只能回答比较非受损DNA成功的现代人和尼安德特人,是否在某些时候他们的DNA韵。这将目前的机会,事实是这两种有杂交早或不。

There has been a hot debate recently about the relationship between the human species and the Neanderthals (The first European were Khoisan 2010). The species are very much related that some researchers and scientists have termed them as the same species. "I would see them as a form of humans that are bit more different than humans are today, but not much," Said Pablo, scientist whose research team conducted a sequence on the Neanderthal man genome (Max Planck Institute for Evolutionary Anthropology 2010),

According to a recently conducted deoxyribonucleic acid test, human beings exhibit some Neanderthal characteristics (Max Planck Institute for Evolutionary Anthropology 2010). The study shows that, in every human being who does not have an African ancestral there is about one to four percent of the genetic makeup matches with the genetic makeup of the Neanderthal (Max Planck Institute for Evolutionary Anthropology 2010),. The Neanderthal who is believed to have died around 30000 years ago is believed to have interbred with the modern man (Homo sapiens). Some study shows that the mating took place somewhere in the Middle East after the modern man had started his migration from Africa to Europe. Comparing the genetic characteristics of the modern early man in Europe and the morphological characteristics of the immediate remains there is a genetic rhyme of the genes with the genetic characteristics of the initial (Early) African modern man. However, there is some variation in the characteristics; the characters which differ between the African Early man and the European early man are deemed to be Neanderthal. The varying characteristics included features such as, the dental structure, external body structure and the overall neurocranial shape. In a prepared statement, lead study author Ed Green of the University of California, Santa Cruz said that in all probability, there must have been a gene flow from Neanderthals to this day human.

Even after thorough researches, there has been no agreement that there is a genetic similarity between the modern human beings and the Neanderthals (Public Library of Science 2010). The proponents of this fact keep on arguing that there are similarities which possibly might have emerged from genetic exchange. However, their rivals claim that very minimal genetic exchange happened. The problems can be resolved by sequencing the Mitochondrial DNA but still the human DNA present in the available fossils is so small to be used effectively (Public Library of Science 2010).

As reported by Public Library of Science (2010), a related problem is that if a Neanderthals fossil gives way to sequences as the modern human-like DNA, those might be discarded as presumed contaminations, regardless of whether they may be endogenous and represent evidence for a close genetic connection or interbreeding between the two groups.

In order to study the relationship that exist between modern humans and the Neanderthals the various difficulties had to be overcome and a conclusion made that four Neanderthal mitochondrion DNA can be distinguished from those of the modern man (Public Library of Science 2010). This gave room for a study to be carried out to determine the genetic relationship between the modern man and the Neandertal man (Public Library of Science 2010)

History

In order to study the process of interbreeding when the migrating modern man met with the Neanderthals, it is very important that their ancestral settlements and migration patterns (Trinkaus 2007). It is also important to determine the ancestors of the modern European man. The Neanderthals are believed to have occupied a large part of the Mediterranean Europe (Trinkaus 2007). The Neanderthals are also believed to have occupied the southwestern Asia. Through such movement pattern and migration there might have been interaction between the Neanderthals and the modern European human (Trinkaus 2007). This is because at some point the Neanderthals displaced the early modern European man in order to settle.

Recently carried out research

A research carried out recently by Max Planck Institute in Leipzig, Germany, saw a sequencing of a Neanderthal DNA in order to determine whether or not there were some similarities with the modern man.

Does the Neanderthal genome explain what makes us different from them?

The study by Pablo shows that there are several differences between the Neanderthals genetic characteristics with the modern man genetic characteristics (Max Planck Institute for Evolutionary Anthropology 2010). The study also shows that the modern man has greatly evolved since they parted ways with the Neanderthal man approximately 500000 years ago (Max Planck Institute for Evolutionary Anthropology 2010). This is one of the reasons that explain the differences between the Neanderthal and the modern man. The difference between the Neanderthal and the modern man is very great for example; these differences give the modern man the ability to make computerized inventions and other artistic things such as poetry instead of drawing on caves and making tools out of stones (Max Planck Institute for Evolutionary Anthropology 2010).

How was the Neanderthal man’s Genome Sequenced?

The study was carried out by studying the DNA present in the bones of the acquired fossils; this is because the bone contains a form of DNA which exists through a very long time even after the organism has died (Max Planck Institute for Evolutionary Anthropology 2010). Research was carried out on 38000 years old bones which were found in Croatia. However, the DNA was contaminated; the scientists used a machine used to sequence DNA. The machine was able to decode the available short DNA strands and got rid of the microbial contamination in the DNA (Max Planck Institute for Evolutionary Anthropology 2010). After this the scientist managed to come with short stretches of the deoxyribonucleic code which after applying computer technology. The short DNA stretches were well combined. Even though the process was successful the process is deemed as not perfect. The scientist decoded 5.3 billion letters of the Neanderthal man DNA code which very erroneous is taking into account that the human DNA contains only 3 billion letters. This means that only two thirds of the DNA was sequenced (Max Planck Institute for Evolutionary Anthropology 2010).

What was the outcome of the research?

The research shows that all human beings who did not trace their ancestral origin to Africa have similar genetic characteristics as the Neanderthal man up to four percent (Max Planck Institute for Evolutionary Anthropology 2010). This means that the Neanderthal man and the modern man interbred and a small trace of their genetic sequence is present to all human beings who are not African considering their ancestral background (Max Planck Institute for Evolutionary Anthropology 2010). The reason why Africans in the sub Sahara are believed not to have Neanderthal characteristics is because the Neanderthal never liver lived in Africa (Max Planck Institute for Evolutionary Anthropology 2010). Some researches have shown that some human characteristics and genes can be traced back to the Neanderthal DNA. This includes a gene which is directly involved in brain development which is believed to have originated from the interbreeding between Homo sapiens and the Neanderthal (Max Planck Institute for Evolutionary Anthropology 2010),

Structure of the early modern European man

Even though it is perceived that the modern early European man is derived from the Middle Paleolithic modern humans (MPMHs) there are some differences which have been exhibited between the two which can only be attributed to the change in DNA (Trinkaus 2007). The main difference between the two is on the structure and shape of the brain for example the difference in the cerebral squamous bone, the growth rate of this bone at infancy is different in the two species. the figure below shows the Cranium of the Oase 2 (Trinkaus 2007). The cranium shows some bones which are similar to the one’s belonging to the early modern European human beings but still there are some differences exhibited. The main differences between the Cranium of Oase 1 and the early modern European human being are the shape and size (Trinkaus 2007).

An examination of this curvature compared to that of the Middle Paleolithic modern humans (MPMHs) there some differences but if compared some categories of the Neanderthal there are some similarities (Trinkaus 2007).The origin of the early European modern man is attributed to the Middle Paleolithic modern humans (MPMHs) but there are some differences between the two which are similar morphological structures which are the same with the Neanderthal (Trinkaus 2007). This means that there was some genetic exchange between the early European modern human beings and the Neanderthals that did not took place with the Middle Paleolithic modern humans. This can only be attributed to interbreeding (Trinkaus 2007).

Source: (Trinkaus 2007)

The study of human fossils of the early European modern man shows gives a record which shows us the fate of the Neandertal (Trinkaus 2007) and their relationship to modern human beings (Trinkaus 2007). The records are clear since the early modern Europeans display both their ancestral characteristics i.e. African modern man and the characteristics of Neandertal. Given the many years that have passed since the extinction of the Neandertal, conducting the comparison process at this point time will not produce reliable results (Trinkaus 2007).

Conclusion

The fact that the modern human DNA is to some percentage related to the DNA of the Neanderthals has sparked of a very serious debate concerning whether the fact are true or forged. Study has shown that about one to four percent of the genetic makeup for the modern humans who do not trace their ancestry to Africa is similar to that of the Neanderthals. Considering the fact that the DNA of a normal human being varies only by two percent with that of a Chimpanzee indeed this debate is worth having.

According to some sources the process of sequencing the human DNA is not a sure process. The DNA contained in fossils of human beings is said to be contaminated and sometimes not adequate enough to carry out a sufficient genetic comparison. However, Max Planck Institute in Leipzig, Germany with the help of modern technology managed to sequence the DNA of a Neanderthal and conducted a comparison with the modern human DNA. Even though the machine used and the method used were termed as not perfect they managed to decode two thirds of the Neanderthal DNA and came up with the statistics that one to four percent of the modern human DNA is similar to that of the Neanderthal. However, the research does not point out any human characteristic which can be directly attributed to the Neanderthal, there has been a theory that the cranium development process of the modern man can somehow be attributed to the Neanderthal man but there are no facts supporting this theory (Trinkaus 2007). The comparison of the characteristics of the modern early European man and the Neanderthal using already recorded paleontological data shows that there are similar characteristics between the Modern Early European human and the Neanderthal (Trinkaus 2007). However the same similarities are not traced back to the Middle Paleolithic modern humans (MPMHs) from whom the early European modern man is alleged to have descended from (Trinkaus 2007). This means that there must have been a genetic exchange during the migration of the early European modern man from Africa (Trinkaus 2007).

From the above we see that the facts concerning the genetic relationship between the modern man and the Neanderthal man are still sketchy at this point. This is because of lack of sufficient archeological proof and scientific facts to prove some of the researches; therefore we are still faced with the question, did Neanderthals and modern human interbreed? This question can only be answered by successfully comparing non impaired DNA of both the modern man and the Neanderthals in order to see whether their DNA rhyme at some point. This will present the opportunity and the facts whether both species had interbreed earlier or not.

 

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