Daohan "Rex" Jiang
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rexjiang.bsky.social
Daohan "Rex" Jiang
@rexjiang.bsky.social
1.2K followers 620 following 240 posts
Evolutionary biologist; postdoc @oistedu.bsky.social; evolutionary theories | complex traits | evolutionary novelties Views are my own. https://rexjiang385518549.wordpress.com/
rexjiang385518549.wordpress.com
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Have been a bit silent recently as I've been working on this new version of our preprint! In this study, we present a generalizable evo-devo model to explore principles of evolutionary innovations. A thread 🧵 ahead about this, and what's new... 1/11
www.biorxiv.org/content/10.1...
A simple model reveals why complex evolutionary innovations follow predictable paths
Determining the principles underlying the origin of novel characters has been a fundamental goal of evolutionary biology. Yet, key mechanisms remain poorly understood, hindered by the lack of a genera...
www.biorxiv.org
1 9 14
rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 11h
I’m wondering if there would be a Dinocephalosaurus version of this…
rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 1d
Driven by personal interest, I started this project on iNaturalist, documenting observations of crocodilians interacting with animals of either the same or different species. Far from comprehensive at the moment, but already got some amazing scenes...

www.inaturalist.org/projects/cro...
Crocodilian Interspecific and Intraspecific Interactions
This project aims to pool observations of both interspecific and intraspecific interactions involving crocodilians (order Crocodylia), making them easier to find. This project is focused on interactio...
www.inaturalist.org
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
At last, thanks & apologies to everyone who went to my talk in #ESEB2025. I said this new version of our manuscript would be online "soon", but it ended up taking this long. 😂 Now that it's here, come & check it out!
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Together, we present a evo-devo model for evolutionary innovation that links patterns to mechanisms, and show principles underlying 3 types of innovations of great interest. The model can hopefully inform a broad type of traits, and I'm excited to think about potential applications! 11/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Expression's also low for the simplest ones, as everyone remained similar to the common ancestor. The peak in between reflect when there's a one-to-many mapping between function & form, e.g., the same ecological adaptation via diverse morphological/physiological means. 10/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
We reveal a non-monotonic relationship between expression divergence & complexity. As predicted, expression divergence is lowest for the most complex innovations. Lineages ended up w/ similar solutions in terms of regulator expression--a phenomenon aka deep homology. 9/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Our model predicts the solution space (in terms of regulator expression) is smaller when the new phenotype to evolve is complex. To confirm it, we simulated lineages evolving toward the same optimal phenotype & checked how complexity (dimensionality) of the optimum affects expression evolution. 8/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
The 3rd type of evolutionary change is the origin of a novel character identity via assembling a novel regulator expression program (sequentially have multiple regulators' local expression levels altered). e.g., the origin of a new cell type. This part is added in this new version. 7/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Simulation results for the above weren't too surprising though. There're some parameter subspaces (in terms of regime of selection & mutational constraint) where these evolutionary changes are likely to happen and some where they tend not to... 6/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
The second is switching between pre-existing identities by turning on/off upstream regulator(s), which is compensated by changes in regulator-effector interactions. The putative example shown here is the back-and-forth change between feathered & scaled states in theropods. 🦖 5/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Under this general modeling framework, we examined 3 types of evolutionary changes, the first being state divergence between body parts w/ conserved identities (e.g., morphological divergence between tetrapod limbs or insect wings), which results from changes in regulator-effector interactions. 4/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
The GRN consists of regulatory genes that specify identities of body parts (e.g., if a limb is arm or leg) & effector genes producing their phenotypic states (e.g., length of the limb). Different kinds of phenotypic novelties are mediated by evolutionary changes at different levels of the GRN. 3/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Developmental constraints plays a key role in phenotypic evolution & innovations, but systematic theorization remains lacking. In light of advances in developmental biology, we propose a generalizable model where development as controlled via a hierarchical gene regulatory network (GRN). 2/11
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 4d
Have been a bit silent recently as I've been working on this new version of our preprint! In this study, we present a generalizable evo-devo model to explore principles of evolutionary innovations. A thread 🧵 ahead about this, and what's new... 1/11
www.biorxiv.org/content/10.1...
A simple model reveals why complex evolutionary innovations follow predictable paths
Determining the principles underlying the origin of novel characters has been a fundamental goal of evolutionary biology. Yet, key mechanisms remain poorly understood, hindered by the lack of a genera...
www.biorxiv.org
1 9 14
rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 13d
You’d be fine, hopefully unlikely to need hospitalization 🙏
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 14d
Literally forgot it was Mid Autumn Festival (lunar calendar Aug 15) yesterday and did take a photo of the moon 🌕
But today’s moon is nice too.
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 19d
So here’s my (1st) #arachtober post: a pair of oval St Andrew's cross spider (Argiope aemula), along with a prey.
A pair of oval St Andrew's cross spider (Argiope aemula) on the web. The bigger one is the female. A pair of oval St Andrew's cross spider (Argiope aemula) on the web. The bigger one is the female. A prey item, which appears to be an orthopteran, is on the left.
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 20d
Congrats to Nonno-san!
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 22d
The topic of resurrection/immortality was explored extensively in this novel. In addition to Sun Kukong himself, revival of the Chinese Emperor Li Shimin and the king of Wuji were also quite wild…
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 23d
BTW: the individual on the left side is a 14yo female. Her name is Hina (kanji: 妃南)--a really cute name IMO!
rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 23d
Visited the Okinawa Zoo today and saw the two giant anteaters “kissing” each other like this. It’s the first time I saw such behavior… #anteater
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · 26d
Two bugs (probably of genus Cletus) are mating, while a third one is watching beside…I’ve never felt so sorry for a bug.
(I’m assuming the third bug is the “loser”, but I’m unfamiliar with this group and don’t know what exactly is going on.)
Two bugs (probably of genus Cletus) are mating on a plant, and another bug is beside. Two bugs (probably of genus Cletus) are mating on a plant, and another bug is beside.
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · Sep 19
Did the ability of movement on water surface evolve by natural selection, or is it a byproduct of other attributes of the caterpillar? Intuitively, the chance of falling into water by chance should be low and it'd be hard for selection to act on it...
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · Sep 19
I tried searching a bit and found this paper. The authors stated that it's motivated by an observation in 2018.

peerj.com/articles/119...
Active behaviour of terrestrial caterpillars on the water surface
Most butterfly and moth larvae (Lepidoptera) are terrestrial. When terrestrial caterpillars accidentally fall into water, they may drown or be preyed upon by aquatic predators before they can safely r...
peerj.com
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rexjiang.bsky.social
Daohan "Rex" Jiang @rexjiang.bsky.social · Sep 19
Saw this caterpillar crawling on water surface today! Apparently it fell into water and was trying to find its way to survival. I suppose it isn't that common a scene to see, is it?
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