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Jumping Genes and the Evolution of Pregnancy

The human genome is made up of over three billion base pairs, the building blocks of DNA, but only a small part of that is actually protein coding DNA. Transposable elements (TEs) are a type of non-coding DNA that makes up approximately half of the human genome, and since their discovery in the 1940s, they have carried a bad reputation. Often referred to as junk DNA or parasitic genes, TEs are a type of mobile genetic element capable of moving around or “jumping’ within the genome. There are two main types of TEs: retrotransposons, which copy themselves and then reinsert the copies back into the genome and DNA transposons, which cut themselves out of the genome and move to a different site (Figure 1). When TEs move around, they sometimes land in the middle of a gene or even another TE, which is often detrimental to the function of that gene or TE. The function and potential benefits of TEs have not always been clear, but research has slowly started to unravel their mysteries. A group of scientists at Yale, lead by Gunter Wagner, recently found that TEs may have been responsible for the evolution of pregnancy in mammals.

Figure 1 : DNA transposon (1), and retrotransposon (2). Image from Broad Institute

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Great Tits and Climate Change: An Experiment to Transform Current Prediction Models

 

Great tit feeding on caterpillar. Credit Kateimi Flickr user.

Background:

Timing is everything for bringing new life into the natural world. Every year, species such as the great tit (Parus major), one of the many song birds found on the British Isles, rely on abundant food to be able to provide enough nutrients for their growing young. The presence of this food is the result of a large cascade–like a line of dominos–that begin with the smallest of microorganisms responding to environmental factors such as temperature and salt concentration. If the timing of one of these falling dominoes is slightly off, many organisms further down the line suffer and may be unable to find food at the most critical times of early offspring growth. Two particular organisms that share the same line of dominoes as the great tit are the pendunculate oak (Quercus robur) and the various caterpillars which feed on the oak’s leaves. [3] Continue reading “Great Tits and Climate Change: An Experiment to Transform Current Prediction Models”

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Inheritance of personality: How much do genes matter?

Picture of meerkats
Extremely social animals like meerkats may benefit from specializing in particular social roles to avoid social conflict, which could create distinct personalities that may persist through time (Carter et al. 2014) Photo credit: © anekoho / Fotolia

Personality. All individuals have one. Yet, what actually contributes to individuality? Although seemingly simple, personality frustrates evolutionary biologists due to its complex and convoluted nature. It is well established that personality can have important evolutionary implications (1, 2, 3, 4, 5), but determining a method to test the genetic underpinnings of personality has proven difficult. Continue reading “Inheritance of personality: How much do genes matter?”

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Going gaga for ferns!

Picture of Lady Gaga and heart-shaped fern gametophyte.
Fig. 1: One of the inspirations behind Li et al. naming an entire fern genus after Lady Gaga was the costume she wore for her performance at the 2010 Grammys, which resembles a gametophyte (image from Duke University).

Background

Hybridization has been shown to play a critical role in the evolution of plants (Rieseberg and Wendel 1993) and molecular studies have allowed scientists to re-evaluate taxonomy through multiple methods besides just morphological characteristics (Li et al. 2012). However, some ferns, such as the cheilanthoid ferns in the family Pteridaceae, had not been re-classified as of 2012 even though they were known to be non-monophyletic (that they didn’t all share a single common ancestor). Li et al. (2012) were particularly interested in a group of about twenty cheilanthoid ferns referred to as the “Cheilanthes marginata group,” which are found in arid habitats ranging from Arizona and Texas all the way to Bolivia. They hoped to distinguish this group from its most closely related fern relatives and revise the taxonomy based on the number of chromosomes (an organism’s condensed DNA) and genetic relatedness. Continue reading “Going gaga for ferns!”

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EmANTcipation: When captured ants rise against their captors

Throughout history, humans have had a fascination with ants, featuring them in fables and folklore (See Aesop’s “The Ant and the Grasshopper”or  Greek mythological Myrmidons). Their social and industrious nature make it easy to see them as human-like, and one cannot help but marvel at adaptations such as underground fungus gardens, herding and tending of aphids, burial of their dead, and their ability to work as a group to accomplish a common goal, to name a few. While most people view ants as kitchen or sidewalk nuisances, researchers who study ants are continuously revealing new and exciting complexities about ant behavior.

Slave-making (also called slave-raiding) in ants occurs when ants leave their nest, enter the nest of another species of ant, steal the developing larvae and/or pupae, bring them back to their own nest, and then rear the captured young into adult workers. Slave-making is a type of social parasitism, meaning that the slave-making ants are benefiting at the expense of the host, or captured, species of ant. This relationship can either be facultative, meaning that the slave-making ant can survive without taking brood from another colony (though they may not be as productive without slave-making), or the relationship can be obligate, meaning that the slave-making ants are unable to survive, usually because they cannot eat or care for their own young, without help from the host. Continue reading “EmANTcipation: When captured ants rise against their captors”