Articles by Marisa Wexler (43 results)

Termites may have evolved sterile castes through hormone signaling changes in their cockroach ancestors. Eusocial insects, like ants, bees, and termites, have rigid caste systems: some individuals reproduce, while others are temporarily sterile workers or permanently sterile soldiers. This division of labor allows colonies to thrive, but the question remains:  how did these species evolve…

New genetic data help explain the rapid adaptation of stickleback fish that invaded freshwater habitats in the 1960s. In 1964, an earthquake shook the islands off the coast of Alaska, transforming the landscape as underwater terraces were thrust above the surface. From this cataclysmic event emerged a series of freshwater pools that became a natural…

For the first time in nearly 15 years, the rat genetic map has been updated. Genetic maps help us navigate uncharted data, but to successfully use them to link genes to complex traits, their resolution must be high enough to yield a manageable list of candidate variants. That’s why genetic maps for mice and humans…

Rapid genomic changes observed in Candida albicans soon after exposure to the oral cavity. Whether or not you treat your body like a temple, it presents a hostile and rapidly-changing environment for the many microorganisms that call you home. In contrast to the microbes that hang out inside humans, those that are cultured in the…

Imprinted genes can have oppositional effects on adult behavior in mice. Mammalian genomes show the marks of a genetic tug-of-war between mothers and fathers. These imprinted genes are marked by epigenetic modifications, which means the expression of an imprinted allele depends on whether it was inherited from the mother or the father. A new report…

Expression analysis provides clues about what makes some peanut strains more susceptible to fungal toxin contamination. In 1960, 100,000 turkeys across hundreds of English poultry farms died from aflatoxin contamination in the peanut meal in their feed. Aflatoxin is a potent carcinogen produced by fungi of the genus Aspergillus, which can grow on peanuts. Although…

A new study reveals genetic changes that affect social behavior in chickens. We have a number of phrases that relate human behavior to that of chickens; for example, when you accuse someone of acting “chicken,” you’re likely calling them a coward. If someone is running around like a chicken with their head cut off, they’re…

Although epigenetic modifications contribute to trait variability, their effect pales in comparison to standing genetic variation. The raw material of evolution is genetic variation, but proponents of the “extended evolutionary synthesis” add a new layer to this model: heritable variation in epigenetics. The packaging and tagging of DNA can alter traits without changing the DNA…

A reanalysis of genes tied to life span in mice reveals only a select few affect aging. Like it or not, you are always getting older. The mechanisms responsible for this fact of life, non-negotiable as it is, remain poorly understood. To identify genes that drive the aging process, researchers typically look for those that…

After 60 years of mystery, researchers have identified the pathogen responsible for White Fat Cell Disease. Water fleas of the genus Daphnia have long been critical tools for studying the ecology and evolution of host-pathogen interactions, but one of their natural pathogens has remained mysterious for more than six decades. In the 1950s, Daphnia magna…

Elaborate genome rearrangements take nesting to the extreme. Oxytricha trifallax is a single-celled virtuoso of genome rearrangement. Oxytricha is a ciliate, and like all ciliates, it has two nuclei: a tiny, germline micronucleus and a large, somatic macronucleus. Mating brings together two micronuclei, and the daughter cell creates a new macronucleus out of the zygotic…