Where Do Genes Come From? Part 2: De novo Genes

Author: Bryan Moyers

Editors: Theresa Mau, Alex Taylor, and Kevin Boehnke

“The probability that a functional protein would appear de novo by random association of amino acids is practically zero.” ~ Francois Jacob, 1977

If you’ve ever gotten into arguments about evolution, you may have heard the argument that goes something like this: A new gene randomly forming is as improbable as a tornado blowing through a junkyard and assembling a working 747. The above quote by Francois Jacob shows that scientists have been pretty skeptical about this idea, too.

But something seeming unlikely doesn’t mean that it doesn’t happen. As we learned last time, most mutations are harmful, and most gene duplications are lost—but the rare times when they are beneficial, a new gene can have a huge effect on species survival.

So, is it possible that a protein-coding gene might form randomly? Continue reading “Where Do Genes Come From? Part 2: De novo Genes”

Of Sporks and Scorpions: Where Do Genes Come From? (Part 1)

Author: Bryan Moyers

Editors: Theresa Mau, Alex Taylor, and Kevin Boehnke

What exactly separates us from other animals?  For that matter, what makes any species or group of species special?  How is life so diverse?  How can cephalopods camouflage themselves so well, and how did platypuses become so bizarre?

Part of the answer is in genes.  Genes are sections of DNA that perform a specific function, usually after being translated into proteins by special cellular machinery.  Every species has genes that code for proteins, but different species have different numbers of genes. Humans have around 20,000, fruit flies have around 18,000, and the tiny water-flea has around 31,000 genes. Different sets of genes produce animals with different structures and functions.

Continue reading “Of Sporks and Scorpions: Where Do Genes Come From? (Part 1)”

What Does Smoking Do to Your DNA?

Authors: Shweta Ramdas

Editors: Irene Park and Kevin Boehnke

Smoking 1
Figure 1. Smoking is known to cause at least 14 different types of cancers, although it is not clear how or why.

 

We have known tobacco to be a cause of many cancers for decades now. It is associated with it least 14 types of cancers (see Figure 1). Less understood is how tobacco causes cancer. The short answer—it causes mutations. Tobacco smoke is a mixture of many chemicals, including at least 60 carcinogens (cancer-causing chemicals).

A trans-national team of researchers has begun unearthing the distinct types of mutations caused by tobacco smoke to better understand the biological pathways leading to tobacco-induced cancer. They found that tobacco causes specific types of DNA damage in organs directly exposed to smoke (like the lungs) and that smoking tobacco generally leads to higher rates of mutation in all tissues. Understanding how the chemicals in tobacco smoke cause mutations can help scientists identify new and emerging mutagens and design better treatment strategies.

Continue reading “What Does Smoking Do to Your DNA?”

It’s all in the family! But how? The biology of inheritance Part 2

Author: Shweta Ramdas

Editors: Molly Kozminsky, Christina Vallianatos, Bryan Moyers

If you haven’t been living under a rock for the last five years, you have definitely come across headlines to the tune of “Researchers Find Gene for X”, where X can be anything from happiness, to political affiliation, to your preference for cilantro. There are quite a few people who respond to these studies with “but surely that’s not genetic!” I work on the genetics of psychiatric disorders and have fielded this question from most people with whom I discuss my research: “Isn’t something like depression just caused by things that happen to you or your upbringing? Why do we place the blame on genetics instead?”

Continue reading “It’s all in the family! But how? The biology of inheritance Part 2”

What the octopus genome can tell us

Author: Shweta Ramdas

Editors: Irene Park, Ada Hagan, Alisha John

The team at MiSciWriters certainly finds cephalopods fascinating, and we aren’t alone. Last year, the octopus (Octopus bimaculoides) was added to the growing list of organisms whose genome sequence is known.

Octopuses belong to a class of organisms called cephalopods, which literally means ‘head-feet’ (members of the cephalopod family have a head and tentacles or arms). These tentacles enable the creatures to do some very clever maneuvering, such as escaping their aquariums to eat crabs outside their tanks. It’s no surprise then that these are the most intelligent amongst invertebrates and now new information about the octopus genome can tell us more about these fascinating creatures.

Continue reading “What the octopus genome can tell us”

Interpreting ancient DNA: Not so easy a caveman could do it

Author: Brooke Wolford

Editors: Alex Taylor, Jimmy Brancho, Bryan Moyers

Imagine the year is 1856 and you are toiling in a quarry in the Neander Valley, a few kilometers from Düsseldorf, Germany. Strangely, something is abruptly sticking out of the landscape. You dig around and find ribs, a skull, and other bones—your best guess is that you have stumbled upon the final resting place of a bear. However, what you have actually found are the first identifiable remains of ancient hominins, later named Homo neanderthalensis.

Continue reading “Interpreting ancient DNA: Not so easy a caveman could do it”

It’s all in the family! The biology of inheritance, part 1

Author: Shweta Ramdas

Editors: Molly Kozminsky, Jimmy Brancho, Kevin Boehnke

 

Harry Potter has his mother’s eyes. From his father, James, he inherits his black hair, his ability to play Quidditch, and a certain predisposition to mischief. We are all unique combinations of our parents, receiving half our DNA from each. In the genetic lottery, our parents’ genes are scrambled and spliced to create a new individual who carries on the family’s long tradition of snoring into one’s sheets. But besides a rickety knee, shortness of stature, and preferred pizza toppings, what else can we blame on our parents?

Continue reading “It’s all in the family! The biology of inheritance, part 1”