By: Ali Alsaadi, Colton Burkhart, and Alexio Trichilo (Stonehill College, BIO323: Evolution, Spring 2026)
A recent study published in Science Advances by Emmanuel Cazottes and colleagues reveals that one of the most important genes in the human body is XIST. It has kept its function over millions of years of evolution, but the way it is controlled has changed dramatically across primates. This research shows that evolution can reshape genetic “control systems” without disrupting essential biological processes, offering new insight into how genes evolve and why this matters for human health.
By: Haley Lussier, Madison Navega, and Madison Warren (Stonehill College, BIO323: Evolution, Spring 2025)
Did you know humans are most closely related to chimpanzees? Chimpanzees are remarkably diverse in their adaptation to different habitats, just like we are. Whether you are from Australia or the United States, your population can adapt to the habitat you are in. One cannot deny that change affects habitats, species, and the planet as a whole. Conservation biology has become a vital field for understanding and preserving biodiversity. One key concept in this field is local genetic adaptation, which ensures a species is well-suited to its environment and retains the potential to adapt over time. The recent Science article “Local genetic adaptation to habitat in wild chimpanzees,” by Dr. Harrison Ostridge and 73 coauthors, investigates the differences in the genetic makeup of wild chimpanzee populations to look for evidence that these differences provide an advantage in different environments. Dr. Ostridge completed this research as part of his Ph.D. dissertation at University College London, where he focused on population genomics and its relationship to disease adaptation.
By: Savannah Jeffrey, Julia Ciccolo, & Julia Bennett (Stonehill College, BIO323: Evolution, Spring 2025)
Overview: In many populations of cave-adapted animals, there is an increased presence of single-nucleotide premature termination codons, known as PTCs, that lead to traits losing function. PTCs are a type of mutation that cause a random stop to genetic replication processes, which can have deleterious effects on how traits are expressed. PTCs have been observed in the genetic makeup of many evolved cave species like cavefish, specifically the Mexican tetra, Astyanax mexicanus. Mexican tetras can be found in central and eastern Mexico, as well as in Texas. They originated in bodies of waters such as lakes and rivers, where eventually some Mexican tetras colonized cave systems and formed new populations. Due to these smaller population sizes in these environments, these mutations are subject to much stronger genetic drift, which occurs when alleles increase or decrease by chance in a population. This phenomenon causes traits to become more common or disappear entirely, thus making a population genetically distinct from their ancestors. Cave environments have their own unique selective pressures and allow the loss of traits to be advantageous for organisms, mainly features like eyesight, pigmentation, and circadian cycling. Allocating resources to these traits in an environment where they are not required provides no benefit to these organisms, therefore the loss of them actually positively impacts the species’ fitness, allowing them to invest in other metabolic processes. Additionally, the majority of PTCs arise in redundant genes, reducing the risk of losing genes that are vital for survival.
By: Emma Foster, Ana Alcantara, Apsara Gurung (Stonehill College, BIO 323 Evolution, Fall 2019)
While humans can taste a variety of flavors, this is not true for all mammals. Researches Dr. Kangli
Zhu and other collaborators recently published the research article
“The loss of taste genes in cetaceans,” and found that they are only
able to detect one out of five sensations of taste. These tastes include
sweet, salty, bitter, umami, and sour, but they can only taste salt.
Taste is important to mammal adaptations, particularly in cetaceans,
which are a group of organisms including whales, dolphins, and
porpoises. Umami and sweet taste sensations are important for finding
and eating nutritious protein- and energy-rich foods. Salt is also an
attractive taste and helps animals maintain sodium levels. Bitter taste
is beneficial for aversion to prevent ingestion of toxic or harmful
foods. Sour taste also prevents the ingestion of potentially unripe or
decayed foods.
Bottlenose Dolphin Image credit: https://ccsearch.creativecommons.org/photos/2a8c0f53-d8c8-41e8-9cae-5f8ff1948cce “A little smile for you” by San Diego Shooter is licensed under CC BY-NC-ND 2.0 Continue reading “Salty Cetaceans”
