## Follow posts tagged #biological sciences in seconds.

Don’t think you’re unique?

Well, in humans, each male and female gamete represents one of about 8.4 million possible chromosome combinations due to independent assortment. The fusion of a male gamete with a female gamete during fertilization will produce a zygote with any of about 70 trillion diploid combinations. If we factor in the variation brought about by crossing over, the number of possibilities is truly astronomical.

It may sound trite, but you really are unique.

Science.

# Bees 1, Computers 0

From Wikipedia:

The Travelling Salesman Problem (TSP) is an NP-hard problem in combinatorial optimization studied in operations research and theoretical computer science. Given a list of cities and their pairwise distances, the task is to find a shortest possible tour that visits each city exactly once.

The problem was first formulated as a mathematical problem in 1930 and is one of the most intensively studied problems in optimization. It is used as a benchmark for many optimization methods. Even though the problem is computationally difficult, a large number of heuristics and exact methods are known, so that some instances with tens of thousands of cities can be solved.

An optimal TSP tour through Germany’s 15 largest cities. It is the shortest among trillions of possible tours visiting each city exactly once.

Alright, so that looks like a lot of math jargon, and I probably just lost 90% of our young-adult readership, but why is the problem relevant?

Well according to Guardian News and Media, scientists at Royal Holloway, University of London have discovered that bees are able to solve the TSP in  moments, while computers can be busy for days with the same problem:

Dr Nigel Raine, from Royal Holloway’s school of biological sciences, said: “Foraging bees solve travelling salesman problems every day. They visit flowers at multiple locations and, because bees use lots of energy to fly, they find a route which keeps flying to a minimum.”

Using computer-controlled artificial flowers to test bee behaviour, his wanted to know whether the insects would follow a simple route defined by the order in which they found the flowers, or look for the shortest route.

After exploring the location of the flowers, the bees quickly learned to fly the best route for saving time and energy.

Obligatory Picture of a Halloween Bee-Cat

If bees, with a brain the size of a grass seed, are able to solve a complex problem (as well as perform all of the day-to-day functions of being a bee), what does this mean for the future of computing?  Do we still have a long way to go?

That moment when you’re taking a practice MCAT and you finish the verbal reasoning section and realize all you have left to get through is the biological sciences section

# Human cryptochrome exhibits light-dependent magnetosensitivity

by Lauren E. Foley, Robert J. Gegear, Steven M. Reppert

Abstract

Humans are not believed to have a magnetic sense, even though many animals use the Earth’s magnetic field for orientation and navigation. One model of magnetosensing in animals proposes that geomagnetic fields are perceived by light-sensitive chemical reactions involving the flavoprotein cryptochrome (CRY). Here we show using a transgenic approach that human CRY2, which is heavily expressed in the retina, can function as a magnetosensor in the magnetoreception system of Drosophila and that it does so in a light-dependent manner. The results show that human CRY2 has the molecular capability to function as a light-sensitive magnetosensor and reopen an area of sensory biology that is ready for further exploration in humans.

(a) A tim-GAL4-driven human CRY2 transgene (tim-GAL4/UAS-hCRY2) rescues magnetic responses in the CRY loss-of-function cryb mutant background. For comparison, naive and trained responses to the magnetic field are shown for wild-type Canton-S flies (left bar set) and for a tim-GAL4-driven Drosophila cry transgene in cryb flies (tim-GAL4/UAS-dcry) (second from left bar set). The UAS-hCRY/+ transgene alone (without the tim-GAL4 driver) did not result in significant magnetosentitive responses (P≥0.05; right bar set). Bars show PI values for naive (white, dcry; or red, hCRY2) and trained (black, dcry; or green, hCRY2) groups. To test whether flies responded to the experimental magnetic field, we either used a one-sample t-test to compare naive PI values with zero (that is, PI value expected with no response to the magnetic field) or a Student’s t-test to compare PI values between trained and naive groups. Numbers represent groups tested. Values are mean±s.e.m. *P≤0.05; **P≤0.01; ***P≤0.001. Genotypes in parentheses: tim-GAL4/UAS-dcry (y w; tim-GAL4/UAS-mycdcry; cryb); tim-GAL4/UAS-hCRY (y w; tim-GAL4/UAS-mychCRY2; cryb); and UAS-dcry/+ (y w; UAS-mychCRY2/+; cryb). (b) Light dependence of magnetic responses rescued by human (h)CRY2 (y w; tim-GAL4/UAS-mychCRY2; cryb). The full-spectrum data are the same as those depicted in a. The irradiance curves for the three light conditions used are the same as those used previously. Bars show PI values for naive (red) and trained (green) groups. To test whether flies responded to the experimental magnetic field, we either used a one-sample t-test to compare naive PI values to zero (that is, PI value expected with no response to the magnetic field) or a Student’s t-test to compare PI values between trained and naive groups. Numbers represent groups tested. Values are mean±s.e.m. **P≤0.01, ***P≤0.001.

(via Wired)

Foley, L., Gegear, R., & Reppert, S. (2011). Human cryptochrome exhibits light-dependent magnetosensitivity Nature Communications, 2 DOI: 10.1038/ncomms1364

i’m majoring in biological sciences but i think it’s becoming more apparent that i enjoy chemistry more than biology not to mention that i absolutely detest biology labs. the only reason why i’m sticking with this major is because the courseload isn’t as intense as chem majors.

but the point is i hate biology lab. so much. at least with chem lab the manual’s straightforward & directly tells you what to do … whereas in bio lab you have to guess everything that you have to do and still have no clue with what you’re doing.

i hate biology lab. biology’s tolerable but god i hate that lab.

Because I’m not going to be able to relax all summer unless I fling my inquiry into the able hands of the universe now,

• is it at all realistic of me to imagine I can double major in Biological Sciences and Film Studies?
• if so, will W&M allow me to do it?

# Hi, my name is Julianna

And I am a professional labeler for the Clemson University Biological Sciences Department.