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Scientists discovered a new retrovirus "fossil" found in the common vampire bat which is homologous to retroviruses in rodents and primates. The results suggest the recent circulation of an active infectious retrovirus and cross-species transmission. The study has been published in the scientific journal Journal of Virology.

A common misconception is that Darwin suggested that something as complex as the eye could not have evolved through natural selection. While the misunderstanding often comes from an incomplete reading of his argument, we have long known that intermediate varieties of eyes (e.g., eyespots, cupped eyes, and complex camera-type eyes) exist in a variety of organisms. Eyes are so common that it was thought that they had evolved independently 40-60 times. More recent molecular work, however, has identified the role of Pax6 genes and their homologs in the formation of eyes during development. The basic information for eye formation appears to have been present in the common ancestor to all bilaterans, and perhaps may be more ancient than that. This interrupted case study examines the history of evidence for eye evolution from Darwin's initial postulates, through evidence of multiple intermediate forms, concluding in an examination of Pax6 homologs. The case is primarily for an introductory biology class but an additional section would be appropriate for upper-level evolution or developmental biology courses.

Even if you feel like you have a pretty good hold on what deoxyribonucleic acid is and how it works, you will still appreciate this video. It might not add greatly to your depth of understanding, but it will please your eyes, tickle your brain, and remind you about the many wonders of the double helix.

While genes determine most of our physical characteristics, the exact combination of genes we inherit, and thus our physical traits, is in part due to a process our chromosomes undergo, known as genetic recombination.