Sexual differences in human cranial morphology: is one sex more variable or one region more dimorphic?

2021 ◽  
Author(s):  
Marco Milella ◽  
Daniel Franklin ◽  
Maria Giovanna Belcastro ◽  
Andrea Cardini
Keyword(s):  
Sexual Differences ◽  
Cranial Morphology

Additional Dermal Ossifications in the Anuran Skull: Morphological Novelties or Archaic Elements?

2011 ◽  
Vol 4 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Sergei V. Smirnov
Keyword(s):  
Common Ancestor ◽  
The State ◽  
Cranial Morphology ◽  
Anterior Portion ◽  
Bombina Orientalis ◽  
Common Event ◽  
Rostral Portion ◽  
Morphological Novelties ◽  
Dermal Bones

Examination of the cranial morphology in Bombina orientalis (Anura: Discoglossidae) revealed the occurrence of additional dermal bones lying: a) between the nasals and frontoparietals, b) between frontoparietals, and c) on the tectum synoticum behind the frontoparietals. The presence of similar bones as well as extra ossifications lying in the midline in the rostral portion of skull was shown to be a rather common event among anurans. Based on the occurrence of bones with similar topology in crossopterygians and different stegocephalians, it was concluded that extra ossifications sporadically appearing in anurans are more likely to be ancient cranial elements than neomorphs. Additional dermal bones found in the anterior portion of the anuran skull are homologous to the postrostrals of crossopterygians; extra ossifications lying between the frontoparietals correspond to the bones with similar topology sporadically appearing in crossopterygians and stegocephalians; and extra bones situated behind the frontoparietals are homologous to the lateral extrascapulars (postparietals of stegocephalians) and the median extrascapular of crossopterygians. These extra bones were proposed to be inherited from the presumed common ancestor of all Gnathostomes and retained in anurans in the state of latent capacities. The sporadic appearance of these bones in anurans results from the phenotypical realization of these latent capacities.

From Phenotype to Genotype And Back Again

2019 ◽  
Author(s):  
J. Richtsmeier ◽  
K.M. Lesciotto
Keyword(s):  
Human Evolution ◽  
Evolutionary Change ◽  
Cranial Morphology ◽  
Phenotypic Trait ◽  
Critical Feature ◽  
Developmental Mechanism ◽  
Experimental Approaches ◽  
Physical Forces ◽  
Collaborative Efforts ◽  
Current Emphasis

Traditionally, anthropologists study evolutionary change throughmorphological analysis of fossils and comparative primate data. For the analysis of the genotypephenotype continuum, the current emphasis on genes is misplaced because genes don’t make structure. Developmental processes make structure through the activity of cells that use instructions specified by genes. A critical mechanism underlying any phenotypic trait is the genetically guided change in developmental events that produce the trait. But even when a developmental mechanism is identified, the links between genetically guided instructions and phenotypic outcome are lengthy, complicated, flexible, and sensitive to physical forces of functioning organs. We use the study of craniofacial phenotypes of craniosynostosis (premature closure of sutures) to demonstrate how patterns produced by the covariation of cranial traits cannot always reveal mechanism. Next we turn to encephalization, a critical feature of human evolution that covaries with cranial phenotypes, and show how experimental approaches can be used to analyze mechanism underlying this well-documented pattern in human evolution. With the realization that no single line of evidence can explain the dramatic changes in cranial morphology that characterize human evolution come fundamental changes in the way we conduct anthropological inquiry - collaborative efforts from scientists with diverse expertise will continue to push the field forward.

scholarly journals Genome-Wide Association Studies Based on Equine Joint Angle Measurements Reveal New QTL Affecting the Conformation of Horses

Genes ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 370 ◽  
Author(s):  
Annik Imogen Gmel ◽  
Thomas Druml ◽  
Rudolf von Niederhäusern ◽  
Tosso Leeb ◽  
Markus Neuditschko
Keyword(s):  
Joint Angle ◽  
Association Studies ◽  
Genome Wide Association ◽  
Cranial Morphology ◽  
Genome Wide Association Studies ◽  
Joint Angles ◽  
Mineral Density ◽  
Mixed Effect ◽  
Stifle Joint ◽  
Genome Wide

The evaluation of conformation traits is an important part of selection for breeding stallions and mares. Some of these judged conformation traits involve joint angles that are associated with performance, health, and longevity. To improve our understanding of the genetic background of joint angles in horses, we have objectively measured the angles of the poll, elbow, carpal, fetlock (front and hind), hip, stifle, and hock joints based on one photograph of each of the 300 Franches-Montagnes (FM) and 224 Lipizzan (LIP) horses. After quality control, genome-wide association studies (GWASs) for these traits were performed on 495 horses, using 374,070 genome-wide single nucleotide polymorphisms (SNPs) in a mixed-effect model. We identified two significant quantitative trait loci (QTL) for the poll angle on ECA28 (p = 1.36 × 10−7), 50 kb downstream of the ALX1 gene, involved in cranial morphology, and for the elbow joint on ECA29 (p = 1.69 × 10−7), 49 kb downstream of the RSU1 gene, and 75 kb upstream of the PTER gene. Both genes are associated with bone mineral density in humans. Furthermore, we identified other suggestive QTL associated with the stifle joint on ECA8 (p = 3.10 × 10−7); the poll on ECA1 (p = 6.83 × 10−7); the fetlock joint of the hind limb on ECA27 (p = 5.42 × 10−7); and the carpal joint angle on ECA3 (p = 6.24 × 10−7), ECA4 (p = 6.07 × 10−7), and ECA7 (p = 8.83 × 10−7). The application of angular measurements in genetic studies may increase our understanding of the underlying genetic effects of important traits in equine breeding.

Infection of American smelt in Lake Ontario and Lake Erie with the microsporidian parasite Glugea hertwigi (Weissenberg)

1972 ◽  
Vol 50 (9) ◽  
pp. 1183-1188 ◽  
Author(s):  
M. Chen ◽  
G. Power
Keyword(s):  
Digestive Tract ◽  
Lake Erie ◽  
Ovarian Tissue ◽  
Lake Ontario ◽  
Parasite Load ◽  
Sexual Differences ◽  
Striking Difference ◽  
Female Fish ◽  
Microsporidian Parasite ◽  
Male Fish

In samples taken monthly throughout the year the percentage of American smelt in Lake Ontario and Lake Erie containing cysts of Glugea hertwigi was 5.2% and 62.7% respectively. Sexual differences in incidence were observed, the significance of which was uncertain as results from the two lakes were contradictory.In male fish infection was almost entirely restricted to the digestive tract with few cysts in the liver, skin, and testes. In female fish the digestive tract and ovaries were similarly infected.Seasonal fluctuations in Glugea infection were obvious and seemed correlated with the gonadal cycle. In both sexes the highest parasite load corresponded with the onset of maturation.A striking difference in fecundity between the two smelt populations was attributed to the Glugea infection. In females parasite cysts replaced ovarian tissue, causing a reduction in the number of maturing eggs.

Sexual Difference, Animal Difference: Derrida and Difference “Worthy of Its Name”

Hypatia ◽  
2009 ◽  
Vol 24 (2) ◽  
pp. 54-76 ◽  
Author(s):  
Kelly Oliver
Keyword(s):  
Sexual Difference ◽  
Sexual Differences ◽  
Binary Opposition ◽  
Infinite Variety

I challenge the age-old binary opposition between human and animal, not as philosophers sometimes do by claiming that humans are also animals, or that animals are capable of suffering or intelligence, but rather by questioning the very category of “the animal” itself. This category groups a nearly infinite variety of living beings into one concept measured in terms of humans—animals are those creatures that are not human. In addition, I argue that the binary opposition between human and animal is intimately linked to the binary opposition between man and woman. Furthermore, I suggest that thinking through animal differences or differences among various living creatures opens up the possibility of thinking beyond the dualist notion of sexual difference and enables thinking toward a multiplicity of sexual differences.

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