This is a topic I’ve been wanting to do for a while. Though it can be said that many scientists who investigate topics receive public outcry to a return of racial segregationist ideology in academia to an unfair extent. It would be odd however to apply the same towards Richard Fuerle, and not in any ironic way. He basically peddled the Carleton Coon Multiregional Theory that not even Multi-regionalists would buy, but a quick Google search will lead you to those who would (not the most unbiased group).
The intent of this article is to show how a decent chunk of Fuerle’s arguments are indeed outdated and doesn’t jive with current evidence. While not a review of the whole book, this post will demonstrate enough basic facts that should convince you to discourage his arguments.
First page (the hardest in my opinion) and none in biology. For reference, I encourage commenters to cite from the book if they take issue with my criticisms, as I’m only paraphrasing from this point forward simply because of this.
Quick and simple (and somewhat setting a pattern), this is a trait that RR has talked about in the past with others still getting it wrong. Rather than a reduced or adaptive specialization, bone density in modern European came as a result of sedentary behavior from the Neolithic.
Sedentary living among Sub Saharans is far more recent, even with crops going back several millennia B.C.E intensification wasn’t that common until plantations were used during the slave trade. Shifting Cultivation, though variable, was the norm. I’ll touch upon this in a future article on the African Neolithic.
One of his other pitfall were the implications pf Shovel Teeth in Modern Populations.
- The high rate of such is indicative of modern phylogenic ancestry, supporting the case of Asians.
- The trait in Asians derives from Peking Man.
Both are pretty much refuted by archaic and modern variants being different. And contra to the expectations of his estimates of human divergences being millions of years old, Europeans are closer to Modern Africans than Neanderthals in dentition. This also refutes assertion on the primitive nature of Africans compared to other humans in the case of phylogenics. On the particular features, it’s another story.
In this case there’s no need to look any further than the works of Joel Irish, who I’m willing to bet is unparalleled in this topic in modern research.
Retention of primitive features was something that went back to African migrants into Eurasia, Homo Sapiens both recent and past having long retained archaic traits.
We recently examined whether or not a universal criterionfor dental modernity could be deﬁned (Bailey and Hublin2013). Like cranial morphology, dental morphology shows amarked range of variation; so much that multiple geographicdental patterns (e.g., Mongoloid, Proto-Sundadont, Indodont,Sub-Saharan African, Afridont, Caucasoid, Eurodont, Sun-dadont, Sinodont) have been identiﬁed in recent humans(Hanihara 1969,1992; Mayhall et al. 1982; Turner 1990;Hawkey 1998; Irish 1998,2013; Scott et al. 2013). Ouranalysis conﬁrmed that, while some populations retain higherfrequencies of ancestral (i.e., primitive) dental traits [e.g.,Dryopithecus molar, moderate incisor shoveling (Irish 1997)]and others show higher frequencies of recently evolved (i.e.,derived) dental traits [e.g., double shoveling, four-cuspedlower molars (Turner 1983; Irish and Guatelli-Steinberg2003)], all recent humans show some combination of bothprimitive and derived traits (Bailey and Hublin 2013).
Africans tend to have higher frequencies in retained features, but in the context of recent Eurasian variants, this is to be expected and Irish have actually used this data to support an African dispersal.
Assuming that phenetic expression approximates genetic variation, previous dental morphological analyses of Sub-Saharan Africans by the author show they are unique among the world’s modern populations. Numerically-derived affinities, using the multivariate Mean Measure of Divergence statistic, revealed significant differences between the Sub-Saharan folk and samples from North Africa, Europe, Southeast Asia, Northeast Asia and the New World, Australia/Tasmania, and Melanesia. Sub-Saharan Africans are characterized by a collection of unique, mass-additive crown and root traits relative to these other world groups. Recent work found that the most ubiquitous of these traits are also present in dentitions of earlier hominids, as well as extinct and extant non-human primates; other ancestral dental features are also common in these forms. The present investigation is primarily concerned with this latter finding. Qualitative and quantitative comparative analyses of Plio-Pleistocene through recent samples suggest that, of all modern populations, Sub-Saharan Africans are the least derived dentally from an ancestral hominid state; this conclusion, together with data on intra- and inter-population variability and divergence, may help provide new evidence in the search for modern human origins.
The same was done by his colleague who first posited an West Asian origin as Fuerle did (undoubtedly on much firmer grounds). Has recently integrated this into modern OOA.
To date, the earliest modern human fossils found outside of Africa are dated to around 90,000 to 120,000 years ago at the Levantine sites of Skhul and Qafzeh. A maxilla and associated dentition recently discovered at Misliya Cave, Israel, was dated to 177,000 to 194,000 years ago, suggesting that members of the Homo sapiens clade left Africa earlier than previously thought. This finding changes our view on modern human dispersal and is consistent with recent genetic studies, which have posited the possibility of an earlier dispersal of Homo sapiens around 220,000 years ago. The Misliya maxilla is associated with full-fledged Levallois technology in the Levant, suggesting that the emergence of this technology is linked to the appearance of Homo sapiens in the region, as has been documented in Africa.
This then smoothly glides into the next topic.
Thus we also find that the basis of modern diversification is recent, as in below 50k in age.
On the appearance of Modern East Asian and Native Americans Traits,
Our results show strong morphological affinities
among the early series irrespective of geographical origin,
which together with the matrix analyses results
favor the scenario of a late morphological differentiation
of modern humans. We conclude that the geographic
differentiation of modern human morphology is a late
phenomenon that occurred after the initial settlement
of the Americas.
On the features of earlier Paleoamericans.
During the last two decades, the idea held by some
late 19th and early 20th century scholars (e.g., Lacerda
and Peixoto, 1876; Rivet, 1908) that early American populations
presented a distinct morphological pattern from
the one observed among recent Native Americans, has
been largely corroborated. Studies assessing the morphological
affinities of early American crania have shown
that crania dating to over seven thousand years BP generally
show a distinct morphology from that observed in
later populations. This observation is better supported in
South America, where larger samples of early specimens
are available: population samples from central Brazil
(Lagoa Santa; Neves and Hubbe, 2005; Neves et al.,
2007a) and Colombia (Bogota´ Savannah; Neves et al.,
2007b) as well as in isolated specimens from Southeast
Brazil (Capelinha; Neves et al., 2005), Northeast Brazil
(Toca dos Coqueiros; Hubbe et al., 2007) and Southern
Chile (Palli Aike; Neves et al., 1999). Distinct cranial
morphology has also been observed in early skulls from
Meso-America (Mexico; Gonzalez-Jose´ et al., 2005) and
North America (Jantz and Owsley, 2001; Powell, 2005).
This evidence has recently demonstrated that the
observed high levels of morphological diversity within
the Americas cannot simply be attributed to bias resulting
from the small available samples of early crania, as
was previously suggested (Van Vark et al., 2003).
Recent Native American cranial morphology varies
around a central tendency characterized by short and
wide neurocrania, high and retracted faces, and high
orbits and nasal apertures. In contrast, the early South and
Meso-American (hereafter Paleoamerican) crania
tend to vary around a completely different morphology:
long and narrow crania, low and projecting faces, and
low orbits and nasal apertures (Neves and Hubbe, 2005).
These differences are not subtle, being of roughly the
same magnitude as the difference observed between
recent Australian aborigines and recent East Asians
(Neves and Hubbe, 2005; Neves et al., 2007a,b; but see
Gonza´lez-Jose´ et al., 2008 for a different opinion). When
assessed within the comparative framework of worldwide
craniometric human variation, Paleoamerican groups
show morphological affinities with some Australo-Melanesian
and African samples, while Amerindian groups
Earlier waves of Native Americans were replaced by later waves of migrants from Asia with latter specializations.
The same can be demonstrated in Africa.
For the second half of the Late Pleistocene and the period pre-ceding the Last Glacial Maximum (LGM) (i.e., MIS 3), the only twosites with well preserved and securely dated human remains areNazlet Khater 2 (38 ±6 Ky, Egypt; Crevecoeur, 2008) and Hofmeyr(36.2 ±3.3 Ky, South Africa; Grine et al., 2007). These fossilsrepresent additional evidence for Late Pleistocene phenotypicvariability of African sub-groups. The Hofmeyr specimen exhibitsthe greatest overall similarities to early modern human specimensfrom Europe rather than to Holocene San populations from thesame region (Grine et al., 2007). Moreover, the Nazlet Khater 2specimen preserves archaic features on the cranium and themandible more comparable to those of Late Middle Pleistocene and
early Late Pleistocene fossils than to chronologically closer recentAfrican populations (Crevecoeur, 2012). These specimens representaspects of modern human phenotypic variation not found in cur-rent populations. This situation seems to have lasted until thebeginning of the Holocene in the African fossil record, not only inthe northeastern part of the continent (Crevecoeur et al., 2009) butalso in the west central (Iwo Eleru, Nigeria, Harvati et al., 2011;Stojanowski, 2014) and eastern regions (Lukenya Hill, Kenya,Tryon et al., 2015). During the Holocene, an increased homogeni-zation of cranio-morphological features is documented, particu-larly within sub-Saharan Africa, with its peak during and after theBantu expansion from 6 Ky ago (Ribot, 2011).
Without Ambiguity, the EUP like Hofmeyr skull was found to be archaic relative to recent SSA.
Although the supraorbital torus is comparable in thickness to that in UP crania, its continuous nature represents a more archaic morphology ( 26 ). In this regard, Hofmeyr is more primitive than later sub-Saharan LSA and North African UP specimens (such as Lukenya Hill and Wadi Kubbaniya), even though they may have a somewhat thicker medial supraorbital eminence. Despite its glabellar prominence and capacious maxillary sinuses, Hofmeyr exhibits only incipient frontal sinus development, a condition that is uncommon among European UP crania ( 27 ). The mandibular ramus has a well-developed gonial angle, and the slender coronoid process is equivalent in height to the condyle. The mandibular (sigmoid) notch is deep and symmetrical, and its crest intersects the lateral third of the condyle. The anterior margin of the ramus is damaged, but it is clear that there was no retro- molar gap. The Hofmeyr molars are large. The bucco- lingual diameter of M 2 exceeds recent African and Eurasian UP sample means by more than 2 SD (table S3). Radiographs reveal cynodont molars, although pulp chamber height is likely to have been affected by the deposition of secondary dentine in these heavily worn teeth. Thus, Hofmeyr is seemingly primitive in comparison to recent African crania in a number of features, including a prominent glabella; moderately thick, continuous supraorbital tori; a tall, flat, and straight malar; a broad frontal process of the maxilla; and comparatively large molar crowns.
One of unique traits to Modern Eurasians is a measurable increase in Cranial Index.
Craniometric data have been collected from published and unpublished reports of numerous authors on 961 male and 439 female crania from various sites in Subsaharan Africa spanning the last 100 ka. All data available in the literature, irrespective of their “racial” affinities, were used to cover the prehistoric and early historic times (up to 400 a BP). Samples covering the last 400 years do not include European colonists and consist of skeletons exavated at archeological sites, collected by early European travelers and derived from anatomical collections. Cranial capacity, depending on the mode of its calculation, has decreased by 95–165 cm3 among males and by 74–106 cm3 among females between the Late Stone Age (30-2 ka BP) and modern times (last 200 years). Values of the cranial index did not show any trend over time and their averages remained in the dolichocephalic category. The decrease in cranial capacity in Subsaharan Africa is similar to that previously found in Europe, West Asia, and North Africa, but, unlike the latter, it is not accompanied by brachycephalization. © 1993 Wiley-Liss, Inc.
It’s worth noting in even Fuerle’s data, despite emphasizing this trait in a singular black example, Caucasians have a larger browridge by comparison. Black were described as small in comparison in this trait. Likewise, the data indicates that the skulls were generally smoother and rounder with more receded Cheekbones.
On a comprehensive look on how these difference, this paper seems sufficient.
Morphological characteristics of the orbit that are most variable among the
African, Asian, and European samples include orbital volume (obv), orbital depth (obd), basion-superior orbit (bso), and orbital breadth (obb), and are also those that contribute most to group separation in the multivariate analyses. Interorbital breadth (dkb), biorbital Samples Asian European African 20.9960 31.2139 Asian 15.4776 Samples Asian European African 1.80745 3.19353 Asian 3.70921
68 breadth (ekb), and basion-orbitale (bio) were not found to be statistically different among these samples, however the low significance value for basion-orbitale in a one-way analysis of variance (p = 0.055) indicates that some degree of divergence exists among them. Additionally, while a significance test was not carried out for “shape” of the orbital margins, it is clear that general differences exist among groups. The most notable difference is between the Asian and African samples, in which the former possesses high and narrow orbits (a more rounded shape), and the latter is characterized by lower and wider orbital margins (a more rectangular shape).
This current investigation reveals that the orbital
margins vary in association with these long-term evolutionary changes, becoming
vertically shorter, horizontally elongated, more frontated, and retracted relative to basion, with a greater degree of reduction in the inferior orbital margins.
In otherwords, the Rectangular Shape of “Negroids” are a retention, but towards a baseline Sapiens trend.
The wide rectangular shape of the orbital margins resulting from a shift in relative
size of orbital height and orbital breadth is highly characteristic of anatomically modern humans from the Upper Paleolithic in Europe and Asia (chapter 5), and extant groups from Sub-Saharan Africa (chapter 3). Following the Upper Paleolithic however, the trend toward superoinferiorly shorter and more elongated orbits associated with a grade shift in craniofacial form began to reverse, and the orbital margins become taller and narrower, taking on a more rounded shape. This more recent trend has also been documented among East Asian groups dating to the Holocene (Brown & Maeda, 2004; Wu et al. 2007), and is investigated as part of a larger examination of orbital change through the European Upper Paleolithic in chapter 5 of this thesis.
On the specifics, Eurasians.
In looking at size and shape of the orbital margins it can be seen that orbital breadth does not vary in relation to cranial shape, but does decrease as the upper facial index increases, with the same being true of biorbital breadth. In contrast, orbital height is positively correlated with both shape features, which one might expect particularly in relation to the upper facial index, in which a vertical increase in facial height and decrease in facial width would be assumed to affect in a similar way these same dimensions of the orbit. However, Brown & Maeda (2004) found that throughout the Neolithic in China, orbital height increases substantially even while facial height is reduced in that region.
In nearly every case, orbital variables are more highly correlated with shape of the
face than with shape of the head, which is understandable given their inclusion in the facial framework. However, the relationship between basion-orbitale and basion-superior orbit is negatively correlated with both cranial and facial shape variables and to approximately the same degree. This is of particular interest given that the upper facial index comprises two variables that indicate the relationship between height and width of the face in the coronal plane, though measures of basion-orbitale and basion-superior orbit lie in the parasagittal plane. Orbital depth also decreases in association with increased facial height and decreased facial breadth, but is not statistically related to change in cranial shape. This too is surprising given that orbital depth might be expected to decrease more as a result of anterior-posterior shortening of the skull rather than in relation to a narrowing and elongation of the face. 104 Although the direction and magnitude of the relationship between orbital morphology and craniofacial shape largely mimics observed changes in orbital features during the last 30,000 years in Western Europe (section 5.4 above), orbital size deviates slightly from this pattern. Both orbital volume and the geometric mean of orbital height, breadth, and depth remained relatively unchanged since the Upper Paleolithic, however both show a statistically significant negative relationship to the upper facial index, meaning that as the face becomes taller and narrower, space within the orbits is diminished.
Brown and Maeda (2004) show that among skulls of Australian Aborigines and
Tohoku Japanese, which represent changing craniofacial form since the end of the
Pleistocene, orbital volume is highly correlated with supraorbital breadth, lower facial prognathism, and shape of the orbital margins. Among these crania a broader
supraorbital region, more projecting facial skeleton and lower orbital index (more
rectangular shape) are associated with a larger orbital volume. Change in these features, including a strong trend toward higher and narrower orbits, is considered to reflect a decrease in orbital volume that occurred throughout the Holocene in China (Brown & Maeda, 2004).
Africans’ Prognathism and inter Orbital breath can be accounted for here. Pg 13. Explains an association between interorbital breadth and prognathism. Within South Africans, however, wide breadth compensates for a low prognathic profile on page 229-230. In Africans, compare to African Americans, it is more variable. On Page 216 it notes how the role for robust craniofacial features do not correlate with browridge size. Uncorrelated features can be explained by geography for instance.
Richard Fuerle noted the particularly archaic nature of the 100-300k Kabwe/Broken Hill skull in contrast to Modern Humans in Ethiopia. He, in totality with modern “retentions”, asserted that this proved that African pecularities were long standing and postulated that the Middle East was the actual home of human origins.
Some problems with this logic are similar findings In Europe and Asia. Despite being contemporary with Neanderthals by context, the morphology of the Ceprano skull is closer to the LCA with Sapiens.
Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia.
The number of Late Pleistocene hominin species and the timing of their extinction are issues receiving renewed attention following genomic evidence for interbreeding between the ancestors of some living humans and archaic taxa. Yet, major gaps in the fossil record and uncertainties surrounding the age of key fossils have meant that these questions remain poorly understood. Here we describe and compare a highly unusual femur from Late Pleistocene sediments at Maludong (Yunnan), Southwest China, recovered along with cranial remains that exhibit a mixture of anatomically modern human and archaic traits. Our studies show that the Maludong femur has affinities to archaic hominins, especially Lower Pleistocene femora. However, the scarcity of later Middle and Late Pleistocene archaic remains in East Asia makes an assessment of systematically relevant character states difficult, warranting caution in assigning the specimen to a species at this time. The Maludong fossil probably samples an archaic population that survived until around 14,000 years ago in the biogeographically complex region of Southwest China.
Our results indicate that the Hexian teeth are metrically and morphologically primitive and overlap with H. ergaster and East Asian Early and mid-Middle Pleistocene hominins in their large dimensions and occlusal complexities. However, the Hexian teeth differ from H. ergaster in features such as conspicuous vertical grooves on the labial/buccal surfaces of the central incisor and the upper premolar, the crown outline shapes of upper and lower molars and the numbers, shapes, and divergences of the roots. Despite their close geological ages, the Hexian teeth are also more primitive than Zhoukoudian specimens, and resemble Sangiran Early Pleistocene teeth. In addition, no typical Neanderthal features have been identified in the Hexian sample. Our study highlights the metrical and morphological primitive status of the Hexian sample in comparison to contemporaneous or even earlier populations of Asia. Based on this finding, we suggest that the primitive-derived gradients of the Asian hominins cannot be satisfactorily fitted along a chronological sequence, suggesting complex evolutionary scenarios with the coexistence and/or survival of different lineages in Eurasia. Hexian could represent the persistence in time of a H. erectus group that would have retained primitive features that were lost in other Asian populations such as Zhoukoudian or Panxian Dadong. Our study expands the metrical and morphological variations known for the East Asian hominins before the mid-Middle Pleistocene and warns about the possibility that the Asian hominin variability may have been taxonomically oversimplified.
Mandibular and dental features indicate that the Hexian mandible and teeth differ from northern Chinese H. erectus and European Middle Pleistocene hominins, but show some affinities with the Early Pleistocene specimens from Africa (Homo ergaster) and Java (H. erectus), as well as the Middle-Late Pleistocene mandible from Penghu, Taiwan. Compared to contemporaneous continental Asian hominin populations, the Hexian fossils may represent the survival of a primitive hominin, with more primitive morphologies than other contemporaneous or some chronologically older Asian hominin specimens.
Our dental study reveals a mosaic of primitive and derived dental features for the Xujiayao hominins that can be summarized as follows: i) they are different from archaic and recent modern humans, ii) they present some features that are common but not exclusive to the Neanderthal lineage, and iii) they retain some primitive conformations classically found in East Asian Early and Middle Pleistocene hominins despite their young geological age.
Middle to Late Pleistocene human evolution in East Asia has remained controversial regarding the extent of morphological continuity through archaic humans and to modern humans. Newly found ∼300,000-y-old human remains from Hualongdong (HLD), China, including a largely complete skull (HLD 6), share East Asian Middle Pleistocene (MPl) human traits of a low vault with a frontal keel (but no parietal sagittal keel or angular torus), a low and wide nasal aperture, a pronounced supraorbital torus (especially medially), a nonlevel nasal floor, and small or absent third molars. It lacks a malar incisure but has a large superior medial pterygoid tubercle. HLD 6 also exhibits a relatively flat superior face, a more vertical mandibular symphysis, a pronounced mental trigone, and simple occlusal morphology, foreshadowing modern human morphology. The HLD human fossils thus variably resemble other later MPl East Asian remains, but add to the overall variation in the sample. Their configurations, with those of other Middle and early Late Pleistocene East Asian remains, support archaic human regional continuity and provide a background to the subsequent archaic-to-modern human transition in the region.
The HLD human sample, primarily the HLD 6 skull but includingthe isolated cranial, dental, and femoral remains, provides a suiteof morphological features that place it comfortably within the pre-viously known Middle to early Late Pleistocene East Asian humanvariation and trends. These Middle-to-Late Pleistocene archaichuman remains from East Asia can be grouped into four chro-nological groups, from the earlier Lantian–Chenjiawo, Yunxian,and Zhoukoudian; to Hexian and Nanjing; then Chaoxian, Dali,HLD, Jinniushan, and Panxian Dadong; and ending with Changyang,Xuchang, and Xujiayao. They are followed in the early LatePleistocene by Huanglong, Luna, Fuyan, and Zhiren, which to-gether combine archaic and modern features.
There is nonetheless substantial variation across the availableEast Asian sample within and across these chronological groupsand especially in terms of individual traits and their combinationswithin specimens (SI Appendix, Figs. S16 and S17 and Tables S10,S12, and S13). However, similar variation within regions andwithin site samples is evident elsewhere during the MPl (as reflectedin the persistent absence of taxonomic consensus regarding MPlhumans; see refs. 19, 23, 41, and 42), and it need not imply morethan normal variation among these fluctuating forager populations.The growing human fossil sample from mainland East Asia,enhanced by the HLD remains, therefore provides evidence ofcontinuity through later archaic humans, albeit with some degreeof variation within chronological groups. As such, the samplefollows the same pattern as the accumulating fossil evidence forMPl (variably into the Late Pleistocene) morphological conti-nuity within regional archaic human groups in Europe (e.g., ref.43), Northwest Africa (e.g., ref. 44), and insular Southeast Asia(e.g., refs. 21 and 24), as well as into early modern humans inEast Africa (e.g., ref. 45). Several divergent peripheral samples[Denisova, Dinaledi, and Liang Bua (46–48)] do not follow thispattern, but they are best seen as interesting human evolutionaryexperiments (49) and not representative of Middle to Late Pleisto-cene human evolution. It is the core continental regions that providethe overall pattern of human evolution during this time period andform the background for the emergence of modern humans.Although there is considerable interregional diversity across theseOld World subcontinental samples, primarily in details of craniofa-cial morphology, these fossil samples exhibit similar trends in primarybiological aspects (e.g., encephalization, craniofacial gracilization).Moreover, all of these regional groups of Middle to Late Pleistocenehuman remains reinforce that the dominant pattern through archaichumans [and variably into early modern humans through continuityor admixture (16, 50, 51)] was one of regional population consistencycombined with global chronological trends.
Fuerle has recently attempted to build a case for the existence
of multiple biological species of humans from a molecular perspective.
Fuerle used comparative genetic distance data involving various
DNA types obtained from a variety of sources for a range of
biological species and subspecies . The results of his review
are summarized in the following table. Additional data involving
non-mtDNA based estimates of the genetic distance between the
gorilla species and the chimpanzees and bonobos have been included
Table 4 would seem to suggest that the Sub-Saharan African
(Bantu) and Australopapuan (Aborigine) genetic difference as measured
by SNP’s is greater than the genetic distance between both
the two species of gorilla (Gorilla gorilla and Gorilla beringei), and
greater than the distance between the common chimpanzee and
the bonobo as measured by mtDNA.
On the basis of this Fuerle suggests that there are only two
consistent courses of action to take regarding re-classification –
splitting or lumping. Either H. sapiens could be split into two species
– Homo africanus which would encompass modern African
populations and Homo eurasianensis which would encompass Eurasian
populations; making the genus Homo consistent in his view,
species-wise with respect to other genera in which the differences
between species are expressed in terms of much smaller genetic
distances; or alternatively the genetic variability within the human
species could be used to typologically define the absolute limits of
what constitutes a vertebrate species, which could then be employed
as a taxonomic baseline in the classification of other species.
This would mean lumping the two gorilla species and the
chimpanzee and the bonobo as single species.
FST reflects the relative amount of total genetic differentiation
between populations, however different measures of genetic distance
involving mtDNA and autosomal loci are simply inappropriate for the purposes of inter-specific comparison as the different
genes involved will have been subject to markedly different selection
pressures and are therefore not likely to have diverged at the
same time . To illustrate this point, this author listed alternative
estimates of the distance between the gorilla species and the
common chimpanzee and bonobo, based on various nuclear loci
and autosomal DNA. The much higher numbers reflect the extreme
variation that can be expected when different genes are considered.
Fuerle’s presentation of the data is also problematic for another
reason, namely he makes no mention of the current
debates surrounding gorilla and chimpanzee/bonobo taxonomy;
as new research on these taxa regularly generates novel and in
some cases wildly variable estimates of genetic distance between
these primates, and there is even some debate over whether the
eastern and western gorillas are separate species .
Curnoe and Thorne have estimated that periods of around two
million years were required for the production of sufficient genetic
distances to represent speciation within the human ancestral lineage
. This indicates that the genetic distances between the
races are too small to warrant differentiation at the level of biological
species, as the evolution of racial variation within H. sapiens
started to occur only 60,000 years ago, when the ancestors of modern
humans first left Africa.