A Preliminary Analysis of the Immunoglobulin Genes in the African Elephant (Loxodonta africana)

The genomic organization of the IgH (Immunoglobulin heavy chain), Igκ (Immunoglobulin kappa chain), and Igλ (Immunoglobulin lambda chain) loci in the African elephant (Loxodonta africana) was annotated using available genome data. The elephant IgH locus on scaffold 57 spans over 2,974 kb, and consists of at least 112 VH gene segments, 87 DH gene segments (the largest number in mammals examined so far), six JH gene segments, a single μ, a δ remnant, and eight γ genes (α and ε genes are missing, most likely due to sequence gaps). The Igκ locus, found on three scaffolds (202, 50 and 86), contains a total of 153 Vκ gene segments, three Jκ segments, and a single Cκ gene. Two different transcriptional orientations were determined for these Vκ gene segments. In contrast, the Igλ locus on scaffold 68 includes 15 Vλ gene segments, all with the same transcriptional polarity as the downstream Jλ-Cλ cluster. These data suggest that the elephant immunoglobulin gene repertoire is highly diverse and complex. Our results provide insights into the immunoglobulin genes in a placental mammal that is evolutionarily distant from humans, mice, and domestic animals

Nonlinear spin control by terahertz-driven anisotropy fields

Future information technologies, such as ultrafast data recording, quantum computation or spintronics, call for ever faster spin control by light. Intense terahertz pulses can couple to spins on the intrinsic energy scale of magnetic excitations. Here, we explore a novel electric dipole-mediated mechanism of nonlinear terahertz-spin coupling that is much stronger than linear Zeeman coupling to the terahertz magnetic field. Using the prototypical antiferromagnet thulium orthoferrite (TmFeO3), we demonstrate that resonant terahertz pumping of electronic orbital transitions modifies the magnetic anisotropy for ordered Fe3+ spins and triggers large-amplitude coherent spin oscillations. This mechanism is inherently nonlinear, it can be tailored by spectral shaping of the terahertz waveforms and its efficiency outperforms the Zeeman torque by an order of magnitude. Because orbital states govern the magnetic anisotropy in all transition-metal oxides, the demonstrated control scheme is expected to be applicable to many magnetic materials