scholarly journals The genetic basis of tail-loss evolution in humans and apes

2021 ◽  
Author(s):  
Itai Yanai ◽  
Bo Xia ◽  
Weimin Zhang ◽  
Aleksandra Wudzinska ◽  
Emily Huang ◽  
...  
Keyword(s):  
Neural Tube ◽  
Incomplete Penetrance ◽  
Tail Loss ◽  
Evolutionary Changes ◽  
Alu Element ◽  
Specific Alternative ◽  
Embryonic Spinal Cord ◽  
Selection For ◽  
Characteristic Style ◽  
Human Neonates

Abstract The loss of the tail is one of the main anatomical evolutionary changes to have occurred along the lineage leading to humans and to the “anthropomorphous apes”1,2. This morphological reprogramming in the ancestral hominoids has been long considered to have accommodated a characteristic style of locomotion and contributed to the evolution of bipedalism in humans3–5. Yet, the precise genetic mechanism that facilitated tail-loss evolution in hominoids remains unknown. Primate genome sequencing projects have made possible the identification of causal links between genotypic and phenotypic changes6–8, and enable the search for hominoid-specific genetic elements controlling tail development9. Here, we present evidence that tail-loss evolution was mediated by the insertion of an individual Alu element into the genome of the hominoid ancestor. We demonstrate that this Alu element – inserted into an intron of the TBXT gene (also called T or Brachyury10–12) – pairs with a neighboring ancestral Alu element encoded in the reverse genomic orientation and leads to a hominoid-specific alternative splicing event. To study the effect of this splicing event, we generated a mouse model that mimics the expression of human TBXT products by expressing both full-length and exon-skipped isoforms of the mouse TBXT ortholog. We found that mice with this genotype exhibit the complete absence of a tail or a shortened tail, supporting the notion that the exon-skipped transcript is sufficient to induce a tail-loss phenotype, albeit with incomplete penetrance. We further noted that mice homozygous for the exon-skipped isoforms exhibited embryonic spinal cord malformations, resembling a neural tube defect condition, which affects ~1/1000 human neonates13. We propose that selection for the loss of the tail along the hominoid lineage was associated with an adaptive cost of potential neural tube defects and that this ancient evolutionary trade-off may thus continue to affect human health today.

scholarly journals The genetic basis of tail-loss evolution in humans and apes

2021 ◽  
Author(s):  
Bo Xia ◽  
Weimin Zhang ◽  
Aleksandra Wudzinska ◽  
Emily Huang ◽  
Ran Brosh ◽  
...  
Keyword(s):  
Neural Tube ◽  
Incomplete Penetrance ◽  
Tail Loss ◽  
Evolutionary Changes ◽  
Alu Element ◽  
Specific Alternative ◽  
Embryonic Spinal Cord ◽  
Selection For ◽  
Characteristic Style ◽  
Human Neonates

The loss of the tail is one of the main anatomical evolutionary changes to have occurred along the lineage leading to humans and to the "anthropomorphous apes"1,2. This morphological reprogramming in the ancestral hominoids has been long considered to have accommodated a characteristic style of locomotion and contributed to the evolution of bipedalism in humans3-5. Yet, the precise genetic mechanism that facilitated tail-loss evolution in hominoids remains unknown. Primate genome sequencing projects have made possible the identification of causal links between genotypic and phenotypic changes6-8, and enable the search for hominoid-specific genetic elements controlling tail development9. Here, we present evidence that tail-loss evolution was mediated by the insertion of an individual Alu element into the genome of the hominoid ancestor. We demonstrate that this Alu element - inserted into an intron of the TBXT gene (also called T or Brachyury10-12) - pairs with a neighboring ancestral Alu element encoded in the reverse genomic orientation and leads to a hominoid-specific alternative splicing event. To study the effect of this splicing event, we generated a mouse model that mimics the expression of human TBXT products by expressing both full-length and exon-skipped isoforms of the mouse TBXT ortholog. We found that mice with this genotype exhibit the complete absence of a tail or a shortened tail, supporting the notion that the exon-skipped transcript is sufficient to induce a tail-loss phenotype, albeit with incomplete penetrance. We further noted that mice homozygous for the exon-skipped isoforms exhibited embryonic spinal cord malformations, resembling a neural tube defect condition, which affects ~1/1000 human neonates13. We propose that selection for the loss of the tail along the hominoid lineage was associated with an adaptive cost of potential neural tube defects and that this ancient evolutionary trade-off may thus continue to affect human health today.

scholarly journals Losses of female song with changes from tropical to temperate breeding in the New World blackbirds

2009 ◽  
Vol 276 (1664) ◽  
pp. 1971-1980 ◽  
Author(s):  
J. Jordan Price ◽  
Scott M. Lanyon ◽  
Kevin E. Omland
Keyword(s):  
Sexual Selection ◽  
New World ◽  
Female Song ◽  
Complex Song ◽  
Evolutionary Changes ◽  
Apparent Relationship ◽  
Song Production ◽  
Selection For ◽  
The Tropics

Birds in which both sexes produce complex songs are thought to be more common in the tropics than in temperate areas, where typically only males sing. Yet the role of phylogeny in this apparent relationship between female song and latitude has never been examined. Here, we reconstruct evolutionary changes in female song and breeding latitude in the New World blackbirds (Icteridae), a family with both temperate and tropical representatives. We provide strong evidence that members of this group have moved repeatedly from tropical to temperate breeding ranges and, furthermore, that these range shifts were associated with losses of female song more often than expected by chance. This historical perspective suggests that male-biased song production in many temperate species is the result not of sexual selection for complex song in males but of selection against such songs in females. Our results provide new insights into the differences we see today between tropical and temperate songbirds, and suggest that the role of sexual selection in the evolution of bird song might not be as simple as we think.

scholarly journals Dramatic niche shifts and morphological change in two insular bird species

2015 ◽  
Vol 2 (3) ◽  
pp. 140364 ◽  
Author(s):  
Per Alström ◽  
Knud A. Jønsson ◽  
Jon Fjeldså ◽  
Anders Ödeen ◽  
Per G. P. Ericson ◽  
...  
Keyword(s):  
Morphological Change ◽  
Morphological Changes ◽  
Bird Species ◽  
The Novel ◽  
Passerine Birds ◽  
Gulf Of Guinea ◽  
Evolutionary Changes ◽  
The Family ◽  
Niche Shifts ◽  
Selection For

Colonizations of islands are often associated with rapid morphological divergence. We present two previously unrecognized cases of dramatic morphological change and niche shifts in connection with colonization of tropical forest-covered islands. These evolutionary changes have concealed the fact that the passerine birds madanga, Madanga ruficollis , from Buru, Indonesia, and São Tomé shorttail, Amaurocichla bocagii , from São Tomé, Gulf of Guinea, are forest-adapted members of the family Motacillidae (pipits and wagtails). We show that Madanga has diverged mainly in plumage, which may be the result of selection for improved camouflage in its new arboreal niche, while selection pressures for other morphological changes have probably been weak owing to preadaptations for the novel niche. By contrast, we suggest that Amaurocichla 's niche change has led to divergence in both structure and plumage.

scholarly journals Does Long-Term Selection for Development Time Result in Canalization: A Test UsingDrosophila melanogaster

2019 ◽  
Author(s):  
Shampa M. Ghosh ◽  
K. M. Satish ◽  
J. Mohan ◽  
Amitabh Joshi
Keyword(s):  
Adult Development ◽  
Development Time ◽  
Larval Density ◽  
Directional Selection ◽  
Stabilizing Selection ◽  
Clear Trend ◽  
Population Means ◽  
Evolutionary Changes ◽  
Selection For

AbstractCanalization denotes the robustness of a trait against genetic or environmental perturbation. Plasticity, in contrast indicates the environmental sensitivity of a trait. Stabilizing selection is thought to increase canalization of a trait, whereas directional selection is often thought to lead to decanalization. However, the relationship between selection, canalization and plasticity remains largely unclear. Experimental evolution is a powerful approach for addressing fundamental questions in evolution. Here, we ask whether long-term directional selection for reduced pre-adult development time inDrosophila melanogasterresults in the evolution of increased canalization for development time, the trait under primary selection. We additionally investigate whether pre-adult survivorship, a trait only secondarily under selection in this experimental regime, also evolves to become canalized. We examine canalization both in terms of stability of population means and of within population variability across two environmental axes. We used four large outbred populations ofD. melanogasterselected for rapid pre-adult development and early reproduction for 295 generations, and four corresponding ancestral control populations that were not under conscious selection for development time or early reproduction. The selected populations had evolved 25% reduction in both development time and pre-adult survivorship at the time of this study. We studied development time and pre-adult survivorship of the selected populations and controls across various combinations ofrearing temperature and larval density. Development time in the selected populations had become more canalized than controls with regard to density, but not temperature. Canalization of development time across density appears to have evolved due to evolutionary changes in the lifehistory and physiology of the selected populations. Pre-adult survivorship, only a secondary correlate of fitness in the selected populations, did not show any clear trend in terms of canalization with regard to either density or temperature, and, overall variation in the trait was greater compared to development time within and across environments. Whether long-term directional selection canalizes or not, therefore, appears to be dependent in a complex way on specific interactions of trait, selection regime and environmental factor in the context of the ecology and physiology of the popualtions under study.

scholarly journals Evolution of organismal stoichiometry in a 50,000-generation experiment withEscherichia coli

2015 ◽  
Author(s):  
Caroline B. Turner ◽  
Brian D. Wade ◽  
Justin R. Meyer ◽  
Richard E. Lenski
Keyword(s):  
Phosphorus Content ◽  
Chemical Elements ◽  
Relative Proportion ◽  
Total Carbon ◽  
Ecological Interactions ◽  
Nitrogen And Phosphorus ◽  
Time Period ◽  
Evolutionary Changes ◽  
Selection For ◽  
Short Time

Organismal stoichiometry refers to the relative proportion of chemical elements in the biomass of organisms, and it can have important effects on ecological interactions from population to ecosystem scales. Although stoichiometry has been studied extensively from an ecological perspective, little is known about rates and directions of evolutionary changes in elemental composition in response to nutrient limitation. We measured carbon, nitrogen, and phosphorus content ofEscherichia colievolved under controlled carbon-limited conditions for 50,000 generations. The bacteria evolved higher relative nitrogen and phosphorus content, consistent with selection for increased use of the more abundant elements. Total carbon assimilated also increased, indicating more efficient use of the limiting element. Altogether, our study shows that stoichiometry evolved over a relatively short time-period, and that it did so in a predictable direction given the carbon-limiting environment.

scholarly journals Anterior dental evolution in the Australopithecus anamensis–afarensis lineage

2010 ◽  
Vol 365 (1556) ◽  
pp. 3333-3344 ◽  
Author(s):  
Carol V. Ward ◽  
J. Michael Plavcan ◽  
Fredrick K. Manthi
Keyword(s):  
Tooth Wear ◽  
Early Evolution ◽  
Dietary Behaviour ◽  
Australopithecus Afarensis ◽  
Crown Height ◽  
Canine Tooth ◽  
Selective Pressures ◽  
Signal Selection ◽  
Evolutionary Changes ◽  
Selection For

Australopithecus anamensis is the earliest known species of the Australopithecus –human clade and is the likely ancestor of Australopithecus afarensis . Investigating possible selective pressures underlying these changes is key to understanding the patterns of selection shaping the origins and early evolution of the Australopithecus –human clade. During the course of the Au. anamensis–afarensis lineage, significant changes appear to occur particularly in the anterior dentition, but also in jaw structure and molar form, suggesting selection for altered diet and/or food processing. Specifically, canine tooth crown height does not change, but maxillary canines and P 3 s become shorter mesiodistally, canine tooth crowns become more symmetrical in profile and P 3 s less unicuspid. Canine roots diminish in size and dimorphism, especially relative to the size of the postcanine teeth. Molar crowns become higher. Tooth rows become more divergent and symphyseal form changes. Dietary change involving anterior dental use is also suggested by less intense anterior tooth wear in Au. afarensis . These dental changes signal selection for altered dietary behaviour and explain some differences in craniofacial form between these taxa. These data identify Au. anamensis not just as a more primitive version of Au. afarensis , but as a dynamic member of an evolving lineage leading to Au. afarensis , and raise intriguing questions about what other evolutionary changes occurred during the early evolution of the Australopithecus –human clade, and what characterized the origins of the group.

The Enhancement Imperative: The Evolutionary Neurophysiology of Durkheimian Solidarity

2003 ◽  
Vol 21 (4) ◽  
pp. 359-374 ◽  
Author(s):  
Michael Hammond
Keyword(s):  
Social Construction ◽  
Social Life ◽  
Uneven Development ◽  
Social Structures ◽  
Reward Circuitry ◽  
Evolutionary Changes ◽  
The Social ◽  
Neurophysiological Studies ◽  
Recent Developments ◽  
Selection For

Durkheimian solidarity, especially in regard to religion, is reanalyzed in terms of recent developments in the neurosciences and evolution. Neurophysiological studies indicate that religious arousers can piggyback on reward circuitry established by natural selection for interpersonal attachments. This piggybacking is rooted in uneven evolutionary changes in cognitive capacities, emotional arousal capabilities, and preconscious screening rules for rewarding arousal release. Uneven development means that only a special class of enhanced arousers embedded in macro social structures can tap some of the reservoirs of expanded arousal release protected by these screening rules. It becomes imperative that part of collective social life offers these special arouser packages. Beginning with religion and inequality, the social construction of enhanced arousers leaves a trail across human history. However, this trail is not quite what Durkheim had in mind.

scholarly journals Defective Neural Tube Closure and Anteroposterior Patterning in Mice Lacking the LIM Protein LMO4 or Its Interacting Partner Deaf-1

2004 ◽  
Vol 24 (5) ◽  
pp. 2074-2082 ◽  
Author(s):  
Kyungmin Hahm ◽  
Eleanor Y. M. Sum ◽  
Yuko Fujiwara ◽  
Geoffrey J. Lindeman ◽  
Jane E. Visvader ◽  
...  
Keyword(s):  
Neural Tube ◽  
Cranial Nerves ◽  
Transcriptional Regulators ◽  
Neural Tube Closure ◽  
Incomplete Penetrance ◽  
Anteroposterior Patterning ◽  
Rib Cage ◽  
Skeletal Defects ◽  
Tube Closure

ABSTRACT LMO4 belongs to a family of transcriptional regulators that comprises two zinc-binding LIM domains. LIM-only (LMO) proteins appear to function as docking sites for other factors, leading to the assembly of multiprotein complexes. The transcription factor Deaf-1/NUDR has been identified as one partner protein of LMO4. We have disrupted the Lmo4 and Deaf-1 genes in mice to define their biological function in vivo. All Lmo4 mutants died shortly after birth and showed defects within the presphenoid bone, with 50% of mice also exhibiting exencephaly. Homeotic transformations were observed in Lmo4-null embryos and newborn mice, but with incomplete penetrance. These included skeletal defects in cervical vertebrae and the rib cage. Furthermore, fusions of cranial nerves IX and X and defects in cranial nerve V were apparent in some Lmo4−/− and Lmo4+/− mice. Remarkably, Deaf-1 mutants displayed phenotypic abnormalities similar to those observed in Lmo4 mutants. These included exencephaly, transformation of cervical segments, and rib cage abnormalities. In contrast to Lmo4 nullizygous mice, nonexencephalic Deaf-1 mutants remained healthy. No defects in the sphenoid bone or cranial nerves were apparent. Thus, Lmo4 and Deaf-1 mutant mice exhibit overlapping as well as distinct phenotypes. Our data indicate an important role for these two transcriptional regulators in pathways affecting neural tube closure and skeletal patterning, most likely reflecting their presence in a functional complex in vivo.

Framework for Selecting Vocabulary for Preliterate Children Who Use Augmentative and Alternative Communication

2019 ◽  
Vol 28 (3) ◽  
pp. 1000-1009
Author(s):  
Allison Bean ◽  
Lindsey Paden Cargill ◽  
Samantha Lyle
Keyword(s):  
Language Impairment ◽  
Augmentative And Alternative Communication ◽  
Developmentally Appropriate ◽  
School Age Children ◽  
Alternative Communication ◽  
School Based ◽  
Selection For ◽  
Nonverbal Children ◽  
Grammatical Structures ◽  
Insufficient Knowledge

Purpose Nearly 50% of school-based speech-language pathologists (SLPs) provide services to school-age children who use augmentative and alternative communication (AAC). However, many SLPs report having insufficient knowledge in the area of AAC implementation. The objective of this tutorial is to provide clinicians with a framework for supporting 1 area of AAC implementation: vocabulary selection for preliterate children who use AAC. Method This tutorial focuses on 4 variables that clinicians should consider when selecting vocabulary: (a) contexts/environments where the vocabulary can be used, (b) time span during which the vocabulary will be relevant, (c) whether the vocabulary can elicit and maintain interactions with other people, and (d) whether the vocabulary will facilitate developmentally appropriate grammatical structures. This tutorial focuses on the role that these variables play in language development in verbal children with typical development, verbal children with language impairment, and nonverbal children who use AAC. Results Use of the 4 variables highlighted above may help practicing SLPs select vocabulary that will best facilitate language acquisition in preliterate children who use AAC.

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