Genetics and Human Cranial Vault Shape: A Reevaluation

The human skull, a complex structure that protects the brain. The question lies on what genetic factor dictates cranial morphology? New shocking evidence was found by researchers at the University of Pittsburgh and KU Leuven that 30 regions of the genome are associated with the shape and structure of the brain. More importantly, 29 of these are new findings that weren't reported prior. Prior research of genes flourished results in rare human conditions. However, lack of awareness was shown on the genetic basis for typical features of the general public.  This awareness will produce enrich results. In addition, the following suggestions paleoanthropology studies, implementing different measures to describe vault shape, and variants in gene association. 
           Among the following suggestions, variants in gene association sheds light on the bigger picture. A discovery of the strong association near genes can dictate different results in formation of the head and skull. This relates to two variants near the gene RUNX2 that could coordinate development of the bone structure of the skull, or having global effects of the cranial vault. Another aspect is three variants BMP2, BBS9 and ZIC2 corresponding to Craniosynostosis. These variants suggest genes could aid in the development. 
        Overall, the human skull is a complex structure. It's clear that unlocking the human genome is a trip down the rabbit hole. As new technologies and methods immerse, more luck in understanding the secrets to be found within the genome that impact the cranial vault.

Links:

https://www.sciencedaily.com/releases/2023/11/231117120657.htm

https://www.nature.com/articles/s41467-023-43237-8#:~:text=The%20cranial%20vault%20in%20humans,genetic%20architecture%20remains%20poorly%20understood

Hypodontia of Maxillary Lateral Incisors

 Hypodontia, also known as tooth agenesis, is a frequent variation found in dental development and could occur as a part of a syndrome or in a nonsyndromic form. Genetic factors are a major component of the formation of these teeth in terms of size and shape. This particular study focuses on a specific variant of MSX1 (MSX1 rs8670). A sample of patients with isolated, maxillary, lateral incisor agenesis and matched controls had the measurements and morphology of their teeth noted. The methods of this analysis were: genotyping the MSX1 rs8670 genetic variant and morphometric measurements with a 2D image analysis. They were both performed for 26 hypodontia patients and 26 matched controls. This genotyping showed that the presence of the T allele increased the risk of upper lateral incisor agenesis to about 6.9 times the risk of individuals without the allele. There were also easily identifiable morphological differences between hypodontia patients and controls and between the unilateral and bilateral agenesis cases. Of all the teeth affected by hypodontia, the crown of the bucco-lingual dimension was the most affected. There was also evidence indicating that there was significant variation in the crown shape with the Carabelli trait of the upper first molars. The overall findings conclude that the MSX1 rs8670 variant does have associations with variations of the morphological outcomes in dentition. However, epigenetic and environmental factors interact with this variant to cause the variation in morphology, not just the variant itself.

The article highlights how genetics is intertwined with environmental factors, creating variation in morphology; in this case, specifically teeth. This demonstrates that a reliance on a singular factor for an outcome is not very common. Further linking of factors are needed to truly understand the observable traits in an individual, beyond just one or the other. I find the results of this analysis to be a beneficial supplement in studying similar variants in dentition in future analysis.

Link to the article “Genetic and Morphological Variation in Hypodontia of

Maxillary Lateral Incisors”: https://doi.org/10.3390%2Fgenes14010231

another related article: https://doi.org/10.1177/154405910808700715

The Bigger the Nostril, the Hotter the Air

It has been found through a study by a team of scientists from Pennsylvania State University that the shape of one’s nostril may share a relationship with the climate of the region that that person’s ancestors descended from. While noses are used for smelling, they are also used to warm and humidify the air that we breathe. It had been found that the more narrow the nostril, the more efficient the nose would be at warming and humidifying the air. Thus, people that descend from colder climates have more narrow nostrils, as they need noses that are more efficient at warming the cold air, and people that descend from warmer climates have wider nostrils, as they do not need noses that are as efficient at warming the already-warm air. It is stated, however, that the climates of past ancestors’ regions are not deciding factors on nose width; other genes may come into play that affect the shape of one’s nose. 

I love studies that center around the morphology of humans, so of course I was very interested reading this article. Reading articles that center around humans evolving to have advantageous traits is so interesting to me because I love to think that there are some humans out there that for some reason have higher-functioning noses than I do. It intrigues me that a larger-nostriled friend might have an easier time breathing in the Canadian wilderness than I would, simply because of the morphology of their nose. The study does make sense, anyhow, that humans in colder regions would evolve to breathe easier, and humans in warmer climates would evolve as to not have noses that are too efficient at heating already-warm air. It makes sense that someone like myself, who descends from a tropical country like the Philippines, has such large nostrils. 

Reason for Flounders being flat found in genomic study

A recent study done by the Julius Maximilian University Wurzburg in Germany has found reason why the flounder is flat in morphology. This has been a topic f discussion for many years and has been a confusing part of flat fishes life cycle. Scientists have had trouble understanding why flounders among other flatfish species would start as a symmetrical larvae, and then reconfigure its whole anatomy in adulthood to be asymmetrical.

The study looked at the genome of two related species to try and uncover the genetic reasoning behind this. The  genomes of related species, the Japanese flounder (Paralichthys olivaceous) and the tongue sole (cynoglossus semilaevas) were sequenced. The researches turned their focus to the genes that were active specifically during metamorphosis when this great change in anatomy takes place. They found a trigger which was a developmental key, Retinoic Acid is the culprit for skin pigment change as well as interacts with the thyroid hormone which is responsible for the transition of the eyes to one side of the head. Through this they discovered that light also has a lot to do with this change as the very same pigments that capture light in the eye are also found in the skin of larval flounder they can sense light differences and increase retinoids acid production based on this.

This is important as flounder among other species of fish are sought after for food as well as economic gain by fisherman and sellers. Flounders sell for a high price on the open market and with overfishing always being a concern as well as just to meet high demand, many people have attempted and are still attempting to raise and farm these fish. Theres been a problem though they have had trouble getting right, as I'm sure you could guess, its metamorphosis! Solving this mystery helps flounder populations as well as the fishing industry as a whole!