Neandertals and Moderns Made Imperfect Mates

Gibbons, Ann

doi:10.1126/science.343.6170.471

Cited by 8 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Or was this selection mostly ecological or cultural in nature? If reproductive barriers had already begun to evolve between Neanderthals and AMH, then these two hominids may have been on their way to becoming separate species before they met again [13, 20, 21]. Or, as we propose here, did differences in effective population size and resulting genetic load between humans and Neanderthals shape levels of Neanderthal admixture along the genome?…”

Section: Introductionmentioning

confidence: 90%

The Strength of Selection against Neanderthal Introgression

2016

View full text Add to dashboard Cite

Hybridization between humans and Neanderthals has resulted in a low level of Neanderthal ancestry scattered across the genomes of many modern-day humans. After hybridization, on average, selection appears to have removed Neanderthal alleles from the human population. Quantifying the strength and causes of this selection against Neanderthal ancestry is key to understanding our relationship to Neanderthals and, more broadly, how populations remain distinct after secondary contact. Here, we develop a novel method for estimating the genome-wide average strength of selection and the density of selected sites using estimates of Neanderthal allele frequency along the genomes of modern-day humans. We confirm that East Asians had somewhat higher initial levels of Neanderthal ancestry than Europeans even after accounting for selection. We find that the bulk of purifying selection against Neanderthal ancestry is best understood as acting on many weakly deleterious alleles. We propose that the majority of these alleles were effectively neutral—and segregating at high frequency—in Neanderthals, but became selected against after entering human populations of much larger effective size. While individually of small effect, these alleles potentially imposed a heavy genetic load on the early-generation human–Neanderthal hybrids. This work suggests that differences in effective population size may play a far more important role in shaping levels of introgression than previously thought.

show abstract

Section: Introductionmentioning

confidence: 90%

The Strength of Selection against Neanderthal Introgression

2016

View full text Add to dashboard Cite

show abstract

“…While rare interbreeding seems the very opposite of assimilation, Neandertal indistinguishability proponents (Villa & Roebroeks, 2014) have adopted non-productivity in an attempt to reconcile assimilation with the low introgression rate, citing mechanisms such as Haldane's rule, a form of reproductive isolation in which hybrid offspring, usually male, are viable but infertile (Mason & Short, 2011). However, as Overmann & Coolidge (2013) observed in their analysis of possible Neandertal-AMH reproductive isolating mechanisms, hybrid sterility has been estimated as taking an average of 2.0 to 4.0 million years to develop in mammals (Fitzpatrick, 2004;Wu, 1992), a span of time that is at least double and up to eight times the length of time separating the two human types (also see discussion in Gibbons, 2014). Could hybrid sterility have developed between Neandertals and AMH in that short a time span?…”

Section: The False Dichotomymentioning

confidence: 99%

The false dichotomy: a refutation of the Neandertal indistinguishability claim

Wynn¹,

Overmann²,

Coolidge³

2021

Preprint

View full text Add to dashboard Cite

In the debate about the demise of the Neandertal, several scholars have claimed that humanity’s nearest relatives were indistinguishable archaeologically, and thus behaviorally and cognitively, from contemporaneous Homo sapiens. They suggest that to hold otherwise is to characterize Neandertals as inferior to H. sapiens, a false dichotomy that excludes the possibility that the two human types simply differed in ways visible to natural selection, including their cognition. Support of the Neandertal indistinguishability claim requires ignoring the cranial differences between the two human types, which have implications for cognition and behavior. Further, support of the claim requires minimizing asymmetries in the quantity and degree of behavioral differences as attested by the archaeological record. The present paper reviews the evidence for cognitive and archaeological differences between the two human types in support of the excluded middle position.

show abstract

“…此后在中国个别古人类中又发现一些在尼人中极多见而在中国其他人类化石中却表现极为不同的特征, 比如云南马鹿洞下颌骨有臼齿后空间 [21] 与尼人一致, 许家窑颞骨中的内耳前半规管相对较小, 外侧半规管相对较大, 后半规管比外侧半规管位置低, 与尼人独有的衍生特征一致, 而与中国其他人类化石不同 [22,23] . 南京直立人头骨的鼻梁特别高耸 [24] ; 陕西大荔头骨的眉脊中 Reich带领的团队 [27,28] [28] . Sankararaman等人 [27] [35,36] .…”

Section: 不足为凭 2003年研究人员报道罗马尼亚peştera Cuunclassified