Special Sections

Published in Volume 16, 2024: Organisms adapted to extreme environmental conditions provide excellent systems to investigate basic questions about the origins of biodiversity. For example, is adaptive evolution the result of standing variation or new mutations? Do different organisms adapt to similar environments through parallel mechanisms?

Published in Volume 16, 2024: Proteins, as the fundamental molecular machinery of life, have evolved through a remarkable array of structural adaptations and functional innovations. This special issue addresses the intricate processes that shape protein evolution beyond gene duplication, focusing on the emergence and diversification of de novo proteins, which emerged from formerly non-coding DNA.

Published in Volume 14, 2022: The fundamental principles of population genetics—including the role of mutation, selection, migration, and genetic drift—were established by evolutionary biologists such as Sewall Wright, J. B. S. Haldane, and Ronald Fisher in the first few decades of the 20th century. Nearly a century later, the field of population genomics leverages advances in genome sequencing, data storage, and bioinformatics to dissect the influence of these population-level forces at a genomic scale. 

Published in Volume 13, 2021: It has been 50 years since Francis Crick, Leslie Barnett, Sydney Brenner, and Richard Watts-Tobin first deduced the nature of the genetic code, revealing how a gene’s nucleotide sequence is related to the encoded protein’s amino acid sequence. Essential to cracking the code was the premise that the genetic code is degenerate: as there are 64 possible codons (i.e., nucleotide triplets) and only 20 standard amino acids, some amino acids must be specified by multiple codons.

Published in Volume 13, 2021: One process that may result in genomic differences between the germline and soma is programmed DNA elimination (also called chromatin diminution). In a range of organisms including unicellular ciliates and various animals such as nematodes and copepods, specific genomic sequences are selectively eliminated from developing somatic nuclei. In hagfishes, lampreys, songbirds, and some arthropods, entire chromosomes are eliminated. Only recently has sequencing data become available for some of these organisms, confirming that many germline-restricted chromosomes contain genes that are expressed in germline cells.