Chapter 1: Introduction


In this module we will learn about sponges, which are - most likely! - the sister group to all other animals, and therefore very important from the perspective of understanding animal evolution. We will also discuss the unique features of sponges that make them excellent models to study regeneration and symbiosis.









Sponge collection video (Orion Beach, Jervis Bay, AU)





Chapter 2: Morphology


This chapter covers sponge morphology, including the diversity of sponge body plans and unifying features present across the phylum, such as body axes and tissue types.







Chapter 3: Cell types


In this chapter we look deeper into sponge bodies, discussing the variety of sponge cell types and their potential relationship to cell types found in other organisms.






Chapter 4: Phylogeny


The chapter on phylogeny covers the highly-disputed phylogenetic position of sponges, as well as relationships between sponge classes.







Chapter 5: Development of Sycon ciliatum


This chapter uses a very well-studied model system, Sycon ciliatum, to follow events during embryonic development, metamorphosis, and growth.








Chapter 6: Regeneration



Sponges have amazing ability to regenerate, including re-aggregation from dissociated cells. This chapter describes different regeneration modes and the cellular background of sponge regeneration. The lab video introduces Sycon capricorn as a model for regeneration studies.






Sponge regeneration in the lab







Chapter 7: Symbiosis


A module on sponges wouldn't be complete without mentioning bacteria, which are not only food for sponges, but also important partners, forming life-long relationships with their sponge hosts.







Chapter 8: ten exciting (and sometimes controversial) papers on sponges published in the last ten years


de Mendoza A, Hatleberg WL, Pang K, et al. (2019) Convergent evolution of a vertebrate-like methylome in a marine sponge. Nat Ecol Evol. 3:1464-1473. doi: 10.1038/s41559-019-0983-2

Gaiti F, Jindrich K, Fernandez-Valverde SL et al. (2017). Landscape of histone modifications in a sponge reveals the origin of animal cis-regulatory complexity. eLife, 6, e22194 doi: 10.7554/eLife.22194

Hudspith M, Rix L, Achlatis M et al. (2021) Subcellular view of host-microbiome nutrient exchange in sponges: insights into the ecological success of an early metazoan-microbe symbiosis. Microbiome. 9:44. doi: 10.1186/s40168-020-00984-w.

Kenny NJ, Francis WR, Rivera-Vicéns RE et al. (2020). Tracing animal genomic evolution with the chromosomal-level assembly of the freshwater sponge Ephydatia muelleri. Nat Commun 11, 3676 doi: 10.1038/s41467-020-17397-w

Leininger S, Adamski M, Bergum B et al. (2014) Developmental gene expression provides clues to relationships between sponge and eumetazoan body plans. Nature Comm. 5: 3905doi: 10.1038/ncomms4905.

Nakayama S, Arima K, Kawai K et al. (2015). Dynamic transport and cementation of skeletal elements build up the pole-and-beam structured skeleton of sponges. Curr Biol. 25: 2549–54. doi: 10.1016/j.cub.2015.08.023.

Pita L, Rix L, Slaby BM et al. (2018) The sponge holobiont in a changing ocean: from microbes to ecosystems. Microbiome. 6:46. doi: 10.1186/s40168-018-0428-1.

Redmond AK, McLysaght A (2021). Evidence for sponges as sister to all other animals from partitioned phylogenomics with mixture models and recoding. Nat Commun 12, 1783 doi: 10.1038/s41467-021-22074-7

Sogabe S, Hatleberg WL, Kocot KM et al. (2019) Pluripotency and the origin of animal multicellularity. Nature 570:519-522. doi: 10.1038/s41586-019-1290-4.

Soubigou A, Ross EG, Touhami Y et al; (2020) Regeneration in the sponge Sycon ciliatum partly mimics postlarval development. Development. 147:dev193714. doi: 10.1242/dev.193714.

Teacher: Maja Adamska