Introducing a decade of progressCellular and developmental biology spans a huge portion of modern biology, so providing a brief synopsis of a decade of progress is a particularly daunting task. Collectively our interests range from a desire to understand how cells develop, replicate, interact, and age to more complex problems concerning how multicellular tissues form and the mechanisms required to ensure organismal-level physiological control and homeostasis throughout life. With this as a backdrop, highlighting just a handful of breakthroughs is challenging, so I apologise in advance for inevitable omissions in outlining some of the key areas where significant breakthroughs are helping to reshape the horizons of cell and developmental biology. I have structured this review to begin with genes, chromosomes, and protein-nucleic acid condensates, moving through to breakthrough technologies, and ending with a discussion of how these developments can revitalise comparative biology.
Genome topology, chromatin, and loop extrusionThe linear arrangement of genes along chromosomes was initially mapped using genetics but was later confirmed and extended by high-throughput genome sequencing. Chromatin immunoprecipitation (ChIP) approaches have enabled us to map or "see" the binding of transcription factors and other protein complexes to specific loci (Park, 2009). Advanced microscopy and fluorescent in situ hybridisation (FISH), which provided a first glimpse of the spatial position of genes within the nucleus, has also been considerably scaled up in the last few years. However, it is the advent of specialised chromosome conformation capture technologies, dependent on physical proximity, that has enabled dimensional maps of genomic architecture to be established (Akgol Oksuz et al., 2021). In addition to providing robust quantitative measures of interactions between different parts of the genome, these contact maps have revealed topologically associated domains (TADs) and contact boundaries relevant for gene regulation in development (Rao et al., 2014). These studies are starting to decipher the architecture and grammar of genomes as well as revealing new phenomena, such as so-called jets or flares (Guo et al., 2022), where the direction of cis interaction (upstream or downstream of the point of study) is skewed to favour certain outcomes. Cohesin, a complex that was previously best known for holding together sister chromatids at mitosis (Gligoris et al., 2014), is heavily implicated in mediating cis-chromosome contacts of this sort, presumably by tethering chromatin loops and propagating directional loop extrusion (Guo et al., 2022;Zhang et al., 2023).
Chromosome biologyThe packaging of DNA into chromosomes as "thread-like structures that are visible as iconic X-shaped structures only during mitosis" has fascinated scientists for hundreds of