scholarly journals Darwinian Positive Selection on the Pleiotropic Effects of KITLG Explain Skin Pigmentation and Winter Temperature Adaptation in Eurasians

2018 ◽  
Vol 35 (9) ◽  
pp. 2272-2283 ◽  
Author(s):  
Zhaohui Yang ◽  
Hong Shi ◽  
Pengcheng Ma ◽  
Shilei Zhao ◽  
Qinghong Kong ◽  
...  
Keyword(s):  
Positive Selection ◽  
Skin Pigmentation ◽  
Winter Temperature ◽  
Pleiotropic Effects ◽  
Temperature Adaptation ◽  
Darwinian Positive Selection

scholarly journals Erratum to: Positive selection in octopus haemocyanin indicates functional links to temperature adaptation

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Michael Oellermann ◽  
Jan M. Strugnell ◽  
Bernhard Lieb ◽  
Felix C. Mark
Keyword(s):  
Positive Selection ◽  
Temperature Adaptation

scholarly journals A Scan for Signatures of Positive Selection in Candidate Loci for Skin Pigmentation in Humans

2006 ◽  
Vol 23 (9) ◽  
pp. 1697-1706 ◽  
Author(s):  
Neskuts Izagirre ◽  
Iker García ◽  
Corina Junquera ◽  
Concepción de la Rúa ◽  
Santos Alonso
Keyword(s):  
Positive Selection ◽  
Skin Pigmentation ◽  
Candidate Loci

scholarly journals Positive selection in admixed populations from Ethiopia

BMC Genetics ◽  
2020 ◽  
Vol 21 (S1) ◽  
Author(s):  
Sandra Walsh ◽  
Luca Pagani ◽  
Yali Xue ◽  
Hafid Laayouni ◽  
Chris Tyler-Smith ◽  
...  
Keyword(s):  
Positive Selection ◽  
T Cell Receptors ◽  
Skin Pigmentation ◽  
Main Role ◽  
Functional Categories ◽  
Adaptive Selection ◽  
Wide Range ◽  
African Populations ◽  
Polygenic Adaptation

Abstract Background In the process of adaptation of humans to their environment, positive or adaptive selection has played a main role. Positive selection has, however, been under-studied in African populations, despite their diversity and importance for understanding human history. Results Here, we have used 119 available whole-genome sequences from five Ethiopian populations (Amhara, Oromo, Somali, Wolayta and Gumuz) to investigate the modes and targets of positive selection in this part of the world. The site frequency spectrum-based test SFselect was applied to idfentify a wide range of events of selection (old and recent), and the haplotype-based statistic integrated haplotype score to detect more recent events, in each case with evaluation of the significance of candidate signals by extensive simulations. Additional insights were provided by considering admixture proportions and functional categories of genes. We identified both individual loci that are likely targets of classic sweeps and groups of genes that may have experienced polygenic adaptation. We found population-specific as well as shared signals of selection, with folate metabolism and the related ultraviolet response and skin pigmentation standing out as a shared pathway, perhaps as a response to the high levels of ultraviolet irradiation, and in addition strong signals in genes such as IFNA, MRC1, immunoglobulins and T-cell receptors which contribute to defend against pathogens. Conclusions Signals of positive selection were detected in Ethiopian populations revealing novel adaptations in East Africa, and abundant targets for functional follow-up.

scholarly journals Positive selection in octopus haemocyanin indicates functional links to temperature adaptation

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Michael Oellermann ◽  
Jan M. Strugnell ◽  
Bernhard Lieb ◽  
Felix C. Mark
Keyword(s):  
Positive Selection ◽  
Temperature Adaptation

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

Alterations during Positive Selection in the Thymus of nackt CD4-Deficient Mice

2000 ◽  
Vol 52 (6) ◽  
pp. 555-562 ◽  
Author(s):  
I. Nepomnaschy ◽  
G. Lombardi ◽  
P. Bekinschtein ◽  
P. Berguer ◽  
V. Francisco ◽  
...  
Keyword(s):  
Positive Selection ◽  
Deficient Mice
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