The Shapes of Birds’ Eggs: Evolutionary Constraints and Adaptations

2021 ◽  
Author(s):  
Robert Montgomerie ◽  
Nicola Hemmings ◽  
Jamie Thompson ◽  
Tim Birkhead
Keyword(s):  
Evolutionary Constraints

scholarly journals Cytogenetic Analysis and Chromosomal Mapping of Repetitive DNA in Melipona Species (Hymenoptera, Meliponini)

2019 ◽  
Vol 158 (4) ◽  
pp. 213-224 ◽  
Author(s):  
Natália M. Travenzoli ◽  
Bárbara A. Lima ◽  
Danon C. Cardoso ◽  
Jorge A. Dergam ◽  
Tânia M. Fernandes-Salomão ◽  
...  
Keyword(s):  
Stingless Bees ◽  
Chromosome Evolution ◽  
Repetitive Sequences ◽  
Sensu Stricto ◽  
Chromosomal Mapping ◽  
Evolutionary Constraints ◽  
Rdna Sites ◽  
Melipona Species ◽  
The Relationship ◽  
Evolutionary Lineages

Stingless bees of the genus Melipona are subdivided into 4 subgenera called Eomelipona, Melikerria, Melipona sensu stricto, and Michmelia according to species morphology. Cytogenetically, the species of the genus Melipona show variation in the amount and distribution of heterochromatin along their chromosomes and can be separated into 2 groups: the first with low content of heterochromatin and the second with high content of heterochromatin. These heterochromatin patterns and the number of chromosomes are characteristics exclusive to Melipona karyotypes that distinguish them from the other genera of the Meliponini. To better understand the karyotype organization in Melipona and the relationship among the subgenera, we mapped repetitive sequences and analyzed previously reported cytogenetic data with the aim to identify cytogenetic markers to be used for investigating the phylogenetic relationships and chromosome evolution in the genus. In general, Melipona species have 2n = 18 chromosomes, and the species of each subgenus share the same characteristics in relation to heterochromatin regions, DAPI/CMA3 fluorophores, and the number and distribution of 18S rDNA sites. Microsatellites were observed only in euchromatin regions, whereas the (TTAGG)6 repeats were found at telomeric sites in both groups. Our data indicate that in addition to the chromosome number, the karyotypes in Melipona could be separated into 2 groups that are characterized by conserved cytogenetic features and patterns that generally are shared by species within each subgenus, which may reflect evolutionary constraints. Our results agree with the morphological separation of the Melipona into 4 subgenera, suggesting that they must be independent evolutionary lineages.

scholarly journals Evolutionary constraints on the plastid tRNA set decoding methionine and isoleucine

2012 ◽  
Vol 40 (14) ◽  
pp. 6713-6724 ◽  
Author(s):  
Sibah Alkatib ◽  
Tobias T. Fleischmann ◽  
Lars B. Scharff ◽  
Ralph Bock
Keyword(s):  
Evolutionary Constraints

Anti-cancer selection as a source of developmental and evolutionary constraints

BioEssays ◽  
2003 ◽  
Vol 25 (11) ◽  
pp. 1035-1039 ◽  
Author(s):  
Frietson Galis ◽  
Johan A.J. Metz
Keyword(s):  
Evolutionary Constraints ◽  
Anti Cancer

Influence of phylogeny on the estimation of diet from dental morphology in the Carnivora

Paleobiology ◽  
2021 ◽  
pp. 1-16
Author(s):  
Samantha S. B. Hopkins ◽  
Samantha A. Price ◽  
Alec J. Chiono
Keyword(s):  
Evolutionary History ◽  
Morphological Data ◽  
Evolutionary Constraints ◽  
Dental Morphology ◽  
Tooth Shape ◽  
Fossil Mammals ◽  
Phylogenetic Constraints ◽  
Substantial Error ◽  
Evolutionary Tempo And Mode ◽  
Vertebrate Skeleton

Abstract Because teeth are the most easily preserved part of the vertebrate skeleton and are particularly morphologically variable in mammals, studies of fossil mammals rely heavily on dental morphology. Dental morphology is used both for systematics and phylogeny as well as for inferences about paleoecology, diet in particular. We analyze the influence of evolutionary history on our ability to reconstruct diet from dental morphology in the mammalian order Carnivora, and we find that much of our understanding of diet in carnivorans is dependent on the phylogenetic constraints on diet in this clade. Substantial error in estimating diet from dental morphology is present regardless of the morphological data used to make the inference, although more extensive morphological datasets are more accurate in predicting diet than more limited character sets. Unfortunately, including phylogeny in making dietary inferences actually decreases the accuracy of these predictions, showing that dietary predictions from morphology are substantially dependent on the evolutionary constraints on carnivore diet and tooth shape. The “evolutionary ratchet” that drives lineages of carnivorans to evolve greater degrees of hypercarnivory through time actually plays a role in allowing dietary inference from tooth shape, but consequently requires caution in interpreting dietary inference from the teeth fossil carnivores. These difficulties are another reminder of the differences in evolutionary tempo and mode between morphology and ecology.

scholarly journals Emergence of SARS-CoV-2 through recombination and strong purifying selection

2020 ◽  
Vol 6 (27) ◽  
pp. eabb9153 ◽  
Author(s):  
Xiaojun Li ◽  
Elena E. Giorgi ◽  
Manukumar Honnayakanahalli Marichannegowda ◽  
Brian Foley ◽  
Chuan Xiao ◽  
...  
Keyword(s):  
Host Species ◽  
Purifying Selection ◽  
New Drugs ◽  
Evolutionary Constraints ◽  
Binding Motif ◽  
The Novel ◽  
Global Pandemic ◽  
Show Evidence ◽  
Human Coronaviruses ◽  
Novel Coronavirus

COVID-19 has become a global pandemic caused by the novel coronavirus SARS-CoV-2. Understanding the origins of SARS-CoV-2 is critical for deterring future zoonosis, discovering new drugs, and developing a vaccine. We show evidence of strong purifying selection around the receptor binding motif (RBM) in the spike and other genes among bat, pangolin, and human coronaviruses, suggesting similar evolutionary constraints in different host species. We also demonstrate that SARS-CoV-2’s entire RBM was introduced through recombination with coronaviruses from pangolins, possibly a critical step in the evolution of SARS-CoV-2’s ability to infect humans. Similar purifying selection in different host species, together with frequent recombination among coronaviruses, suggests a common evolutionary mechanism that could lead to new emerging human coronaviruses.

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