A Switch Between Topological Domains Underlies HoxD Genes Collinearity in Mouse Limbs

Guillaume Andrey, Thomas Montavon, Bénédicte Mascrez, Federico Gonzalez, Daan Noordermeer, Marion Leleu, Didier Trono, François Spitz, Denis Duboule

Science 7 June 2013: Vol. 340 no. 6137 dpi: 10.1126/science.1234167

Editors Summary

During limb development, the time and place of Hox transcription are fixed by respective gene position within the gene cluster. Andrey et al. (p. 1234167; see the Perspective by Rodrigues and Tabin) found that this enigmatic property results from the opposite and successive actions of two large regulatory landscapes located on either side of the mouse Hox locus. In the early phase, one of these topological domains regulates transcription in the proximal limb until a switch occurs toward the other topological domain, which takes over the regulation in the distally developing digits. As a side effect of this antagonistic regulatory strategy, cells in-between have lessened Hox transcription, which generates the wrist.

Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution

Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution

Smith JJ, Kuraku S, Holt C, Sauka-Spengler T, Jiang N, Campbell MS, Yandell MD, Manousaki T, Meyer A, Bloom OE, Morgan JR, Buxbaum JD, Sachidanandam R, Sims C, Garruss AS, Cook M, Krumlauf R, Wiedemann LM, Sower SA, Decatur WA, Hall JA, Amemiya CT, Saha NR, Buckley KM, Rast JP, Das S, Hirano M, McCurley N, Guo P, Rohner N, Tabin CJ, Piccinelli P, Elgar G, Ruffier M, Aken BL, Searle SM, Muffato M, Pignatelli M, Herrero J, Jones M, Brown CT, Chung-Davidson YW, Nanlohy KG, Libants SV, Yeh CY, McCauley DW, Langeland JA, Pancer Z, Fritzsch B, de Jong PJ, Zhu B, Fulton LL, Theising B, Flicek P, Bronner ME, Warren WC, Clifton SW, Wilson RK, Li W.

Nat Genet. 2013 Apr;45(4):415-21, 421e1-2. doi: 10.1038/ng.2568. Epub 2013 Feb 24

Sea lamprey mouth (Photo: T. Lawrence, GLFC)

Emergence and Diversification of Fly Pigmentation Through Evolution of a Gene Regulatory Module

Laurent Arnoult, Kathy F. Y. Su, Diogo Manoel, Caroline Minervino, Justine Magriña, Nicolas Gompel, and Benjamin Prud’homme

Science 22 March 2013: 339 (6126), 1423-1426. doi: 10.1126/science.1233749

TEMPO AND MODE OF MULTICELLULAR ADAPTATION IN EXPERIMENTALLY-EVOLVED SACCHAROMYCES CEREVISIAE

TEMPO AND MODE OF MULTICELLULAR ADAPTATION IN EXPERIMENTALLY-EVOLVED SACCHAROMYCES CEREVISIAE

William C. Ratcliff, Jennifer T. Pentz, Michael Travisano

doi: 10.1111/evo.12101

Multicellular complexity is a central topic in biology, but the evolutionary processes underlying its origin are difficult to study and remain poorly understood. Here we use experimental evolution to investigate the tempo and mode of multicellular adaptation during a de novo evolutionary transition to multicellularity. Multicelled ‘snowflake’ yeast evolved from a unicellular ancestor after 7 days of selection for faster settling through liquid media. Over the next 220 days, snowflake yeast evolved to settle 44% more quickly. Throughout the experiment the clusters evolved faster settling by three distinct modes. The number of cells per cluster increased from a mean of 42 cells after 7 days of selection to 114 cells after 227 days. Between days 28 and 65, larger clusters evolved via a 2-fold increase in the mass of individual cells. By day 227, snowflake yeast evolved to form more hydrodynamic clusters that settle more quickly for their size than ancestral strains. The timing and nature of adaptation in our experiment suggests that costs associated with large cluster size favor novel multicellular adaptations, increasing organismal complexity.

Darwin Day

Moral behavior in animals

Horizontal transfer of expressed genes in a parasitic flowering plant

Horizontal transfer of expressed genes in a parasitic flowering plant

Zhenxiang Xi, Robert K Bradley, Kenneth J Wurdack, K.M. Wong, M. Sugumaran, Kirsten Bomblies, Joshua S Rest and Charles C Davis

BMC Genomics 2012, 13:227 doi:10.1186/1471-2164-13-227

The animal body plan, the prototypic body segment, and eye evolution

The animal body plan, the prototypic body segment, and eye evolution

Walter J. Gehring

Evolution & Development, 14: 34–46.doi: 10.1111/j.1525-142X.2011.00528.x

Selective bird predation on the peppered moth: the last experiment of Michael Majerus

Selective bird predation on the peppered moth: the last experiment of Michael Majerus.

Cook LM, Grant BS, Saccheri IJ, Mallet J.

Biol Lett. 2012 Feb 8. 10.1098/rsbl.2011.1136

Hamilton vs. Kant: pitting adaptations for altruism against adaptations for moral judgment

Hamilton vs. Kant: pitting adaptations for altruism against adaptations for moral judgment

Robert Kurzban, Peter DeScioli, Daniel Fein

Evolution and Human Behavior, doi:10.1016/j.evolhumbehav.2011.11.002