Out-of-Africa theory

Billede

“Present-day Africans trace up to 19% of their genetic ancestry to an extinct archaic hominid species, such as Homo erectus, not found in the DNA of present-day Asians or Caucasians. Out-of-Africa theory RIP.”

Robert Sepehr

DNA Evidence Debunks the “Out-of-Africa” Theory of Human Evolution

Scientific evidence refuting the theory of modern humanity’s  African genesis is common knowledge among those familiar with the most recent scientific papers on the human Genome, Mitochondrial DNA and Y-chromosomes. Regrettably, within mainstream press and academia circles, there seems to be a conspicuous – and dare we say it – deliberate vacuum when it comes to reporting news of these recent studies and their obvious implications.

Read more here at Wake Up World

Neanderthals have not contributed to the genome of African modern human populations because they never lived there and could not have interbred with the ancestors of those populations.

Neanderthals have contributed approximately 1-4% of the genomes of non-African modern humans, although a modern human who lived about 40,000 years ago has been found to have between 6-9% Neanderthal DNA (Fu et al 2015). The evidence we have of Neanderthal-modern human interbreeding sheds light on the expansion of modern humans out of Africa. These new discoveries refute many previous hypotheses in which anatomically modern humans replaced archaic hominins, like Neanderthals, without any interbreeding. However, even with some interbreeding between modern humans and now-extinct hominins, most of our genome still derives from Africa. Neanderthals could not have contributed to modern African peoples’ genomes because Neanderthals evolved and lived exclusively in Eurasia and therefore could not have bred with the humans living in Africa at that time.

For many years, the only evidence of human-Neanderthal hybridization existed within modern human genes. However, in 2016 researchers published a new set of Neanderthal DNA sequences from Altai Cave in Siberia, as well as from Spain and Croatia, that show evidence of human-Neanderthal interbreeding as far back as 100,000 years ago — farther back than many previous estimates of humans’ migration out of Africa (Kuhlwilm et al 2016). Their findings are the first to show human gene flow into the Neanderthal genome as opposed to Neanderthal DNA into the human genome. This data tells us that not only were human-Neanderthal interbreeding events more frequent than previously thought, but also that an early migration of humans did in fact leave Africa before the population that survived and gave rise to all contemporary non-African modern humans.

Read more here at Human Origins

Slightly angled head-on view of a Neanderthal skeleton, stepping forward with the left leg

Neanderthals are named after the valley, the Neandertal, in which the first identified specimen was found. The valley was spelled Neanderthal and the species was spelled Neanderthaler in German until the spelling reform of 1901.

Neanderthal Museum 20060318.jpg

Neandertal-Museum. Neandertal, Germany.

Neanderthals had more robust and stockier builds than modern humans, wider and barrel-shaped rib cages; wider pelvises; and proportionally shorter forearms and forelegs.

Based on 45 Neanderthal long bones from 14 men and 7 women, the average height was 164 to 168 cm (5 ft 5 in) for males and 152 to 156 cm (5 ft) for females. For comparison, the average height of 28 males and 10 females Upper Palaeolithic humans is respectively 176 cm (5 ft 9 in) and 163 cm (5 ft 4 in), though this decreases by 10 cm (4 in) nearer the end of the period based on 21 males and 15 females; and the average in the year 1900 was 163 cm (5 ft 4 in) and 152.7 cm (5 ft), respectively. The fossil record shows adult Neanderthals varied from about 147.5 to 177 cm (4 ft 10 in to 5 ft 10 in) in height, though it is possible that some grew much taller. For Neanderthal weight, samples of 26 specimens found an average of 77.6 kg (171 lb) for males and 66.4 kg (146 lb) for females. Using 76 kg (168 lb), the body mass index for Neanderthal males was calculated to be 26.9–28.2, which in modern humans correlates to being overweight. This indicates a very robust build. The Neanderthal LEPR gene concerned with storing fat and body heat production is similar to that of the woolly mammoth, and so was likely an adaptation for cold climate.

The neck vertebrae of Neanderthals are longer and thicker than those of modern humans, lending to stability, possibly due to different head shape and size. Though the Neanderthal thorax (where the ribcage is) was similar in size to modern humans, the longer and straighter ribs would have equated to a widened mid-lower thorax and stronger breathing in the lower thorax, which are indicative of a larger diaphragm and possibly greater lung capacity. The lung capacity of Kebara 2 was estimated to have been 9.04 L (2.39 US gal). The Neanderthal chest was also more pronounced (expanded front-to-back, or antero-posteriorly). The sacrum (where the pelvis connects to the spine) was more vertically inclined, and was placed lower in relation to the pelvis, causing the spine to be less curved (exhibit less lordosis) and to fold in on itself somewhat (to be invaginated). Such modifications to the spine would have enhanced side-to-side (mediolateral) flexion, better supporting the wider lower thorax. This condition may be normal for Homo, with the condition of a narrower thorax in modern humans being a unique characteristic.

Body proportions are usually cited as being “hyperarctic” as adaptations to the cold, because they are similar to those of human populations which developed in cold climates—the Neanderthal build is most similar to that of Inuit and Siberian Yupiks among modern humans—and shorter limbs equates to higher retention of body heat. Nonetheless, Neanderthals from more temperate climates—such as Iberia—still retain the “hyperarctic” physique. In 2019, English anthropologist John Stewart and colleagues suggested Neanderthals instead were adapted for sprinting because of evidence of Neanderthals preferring more warmer wooded areas over the colder mammoth steppe, and DNA analysis indicating a higher proportion of fast-twitch muscle fibres in Neanderthals than modern humans. He explained their body proportions and greater muscle mass as adaptations to sprinting as opposed to the endurance-oriented modern human physique, as persistence hunting may only be effective in hot climates where the hunter can run prey to the point of heat exhaustion (hyperthermia). They had longer heel bones, reducing their ability for endurance running, and their shorter limbs would have reduced moment arm at the limbs, allowing for greater rotational force at the wrists and ankles without extra exertion of the rotating muscles at the elbows and knees by increasing the speed at which the muscles contracted, causing faster acceleration. In 1981, American palaeoanthropologist Erik Trinkaus made note of this alternate explanation, but considered it less likely.

Homo sapiens neanderthalensis.jpg

The Neanderthal braincase averages 1,600 cm3 (98 in3) for males and 1,300 cm3 (79 in3) for females, within the possible range of modern humans, which is, on average, 1,270 cm3 (78 in3) for males and 1,130 cm3 (69 in3) for females in present-day. For 28 modern human specimens from 190–25 thousand years ago, the average was about 1,478 cc (90.2 cu in) disregarding sex, and modern human brain size is suggested to have decreased since the Upper Palaeolithic. The largest Neanderthal brain, Amud 1, was calculated to be 1,736 cm3 (105.9 in3), one of the largest ever recorded in hominids. Both Neanderthal and human infants measure about 400 cm3 (24 in3).

In Neanderthals, the occipital lobe—operating vision—was much larger than in modern humans, and, similarly, they had larger eyes, probably as an adaptation to lower light conditions in Europe. More brain tissue was devoted to bodily maintenance and control, and, consequently, the cognitive areas of the brain were proportionally smaller than in modern humans, including the cerebellum (operating muscle memory, and possibly language, attention, working memory, social abilities, and thought), the parietal lobes (visuospatial function and episodic memory), the temporal lobes (language comprehension and associations with emotions), the orbitofrontal cortex (decision making), and the olfactory bulb (sense of smell).

The lack of sunlight most likely led to the proliferation of lighter skin in Neanderthals, though light skin in modern Europeans was not particularly prolific until perhaps the Bronze Age.

Genetically, BNC2 was present in Neanderthals, which is associated with light skin colour; however, a second variation of BNC2 was also present, which is associated with darker skin colour in the UK Biobank. It is likely Neanderthal skin colour varied from region to region. The DNA of three Croatian Neanderthals shows they had darker hair, skin, and eye colour than modern Europeans.

In modern humans, skin and hair colour is regulated by the melanocyte-stimulating hormone—which increases the proportion of eumelanin (black pigment) to phaeomelanin (red pigment)—which is encoded by the MC1R gene. There are 5 known variants in modern humans of the gene which cause loss-of-function and are associated with light skin and hair colour, and another unknown variant in Neanderthals (the R307G variant) which could be associated with pale skin and red hair. The R307G variant was identified in a Neanderthal from Monti Lessini, Italy, and possibly Cueva del Sidrón, Spain. However, like in modern humans, red was probably not a very common hair colour because the variant is not present in many other sequenced Neanderthals.

Read more here at Wikipedia

Archaic Admixture in Sub-Saharan Africans

Six-million-year-old Cretan footprints challenge beliefs about human evolution

4 comments

  1. vᚻællKᚱᛁᛗvosᛏ · September 17, 2020

    DNA Evidence Debunks the “Out-of-Africa” Theory of Human Evolution
    https://wakeup-world.com/2013/12/16/dna-evidence-debunks-the-out-of-africa-theory-of-human-evolution/

    Liked by 1 person

  2. germanicunity · September 27, 2020

    Reblogged this on Germanic Unity.

    Like

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