Lightnews — Scholar-powered news

Walid Mawass @wmawass.bsky.social · 1d

Bottom line: detecting consistent selection and additive genetic variance does not guarantee an evolutionary response.
Our study highlights how even with selection + heritability, evolutionary stasis can persist.
🧬 Evolution isn’t always as predictable as we think!
Preprint: tinyurl.com/mr3r5vk3

Contrasting evolutionary outcomes in a human life history trait which is heritable and under consistent unbiased directional selection

Microevolution is well documented in natural populations, yet its persistence as an adaptive process remains debated. Despite widespread directional selection on heritable traits, including life-histo...

tinyurl.com

Walid Mawass @wmawass.bsky.social · 1d

Why? Several possibilities:
– Not enough time (7 generations)
– Small population size → drift
– G×E interactions constraining response
– Hidden life-history trade-offs limiting evolution

1

Walid Mawass @wmawass.bsky.social · 1d

So what’s going on?
We see clear selection on a heritable trait, yet no evolutionary response.
This suggests that contemporary microevolutionary change is inconsistent and unpredictable — even under strong selection.

1

Walid Mawass @wmawass.bsky.social · 1d

Using the Breeder’s Equation and the Robertson–Price covariance, we predicted evolutionary responses.
Only in Charlevoix did both models predict a strong response… that never happened.
In short: selection ≠ evolution, even when theory says it should.

1

Walid Mawass @wmawass.bsky.social · 1d

Across cohorts, mean AFR changed differently across populations.
And when we looked at breeding values, there was no consistent genetic trend either.
(See figure — phenotypic vs. genetic patterns across time.)

1

Walid Mawass @wmawass.bsky.social · 1d

Our focal trait: age at first reproduction (AFR).
Linear models show strong directional selection favoring earlier AFR (see figure 👇).
Quantitative genetic models confirm that AFR is heritable (h² ≈ 0.11).
Yet—things get interesting.

relationship between fitness measure and age at first reproduction for the Charlevoix dataset

1

Walid Mawass @wmawass.bsky.social · 1d

We identified three subpopulations that can be considered semi-independent replicates: they share genetic and historical backgrounds and similar demographic histories as early French settlers spread across Québec.
(These pedigrees were validated in our earlier QG analyses.)

1

Walid Mawass @wmawass.bsky.social · 1d

To tackle this, we needed longitudinal data with pedigree info to track phenotypic and genetic changes over time — in other words, replicated populations where quantitative genetic models are possible.
The historical French-Canadian (Québec) population turned out to be the perfect system.

1

Walid Mawass @wmawass.bsky.social · 1d

Fellow evo-bio folks of BlueSky! 🧬
New preprint out — based on work from my PhD (yes, Chapter 3!) — where I ask:
👉 How predictable and consistent are evolutionary responses to selection in natural populations?
Preprint: tinyurl.com/mr3r5vk3 #evolution #microevolution #quantitativegenetics #preprint

Contrasting evolutionary outcomes in a human life history trait which is heritable and under consistent unbiased directional selection

Microevolution is well documented in natural populations, yet its persistence as an adaptive process remains debated. Despite widespread directional selection on heritable traits, including life-histo...

tinyurl.com

1 1

Walid Mawass @wmawass.bsky.social · Jun 24

One of my favorite posters among those I visited yesterday! Awesome graphics and color palette.

2

Reposted by Walid Mawass

John Novembre @jnovembre.bsky.social · Jun 5

Excited for our publication on how the geographic scale of a sample affects the discovery of rare, deleterious variants to be out this week. With a mix of theory, simulation, and data analysis, we show when samples are narrow vs broad, the number of variants discovered and their frequencies change

PNAS

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...

www.pnas.org

2 26 71

Walid Mawass @wmawass.bsky.social · Mar 31

Yikes!!!

1

Reposted by Walid Mawass

Murillo R. @mufernando.bsky.social · Mar 24

We are excited to share our new preprint describing the inclusion of selection models to stdpopsim, our community-maintained library with an extensive catalog of population genetic models. 1/n
www.biorxiv.org/content/10.1...

www.biorxiv.org

2 20 22

Reposted by Walid Mawass

Joanna Masel @joannamasel.bsky.social · Mar 19

Our latest paper revisits Haldane 1957 on speed limits to adaptation, the paper that triggered neutral theory. We clarify and then significantly extend the theory, and apply the resulting model to @mexpositoalonso.bsky.social's data doi.org/10.1093/gene... 1/14

Substitution load revisited: a high proportion of deaths can be selective

Abstract. Haldane's Dilemma refers to the concern that the need for many “selective deaths” to complete a substitution (i.e. selective sweep) creates a spe

doi.org

8 41 85

Reposted by Walid Mawass

NSF-Simons NITMB @nitmb.bsky.social · Mar 12

This week’s Research-In-Progress meeting features Walid Mawass (@wmawass.bsky.social), postdoctoral scholar in the Berg Lab at the University of Chicago!

Research-In-Progress is a venue for the NITMB community to discuss planned or in-progress work

1 2

Reposted by Walid Mawass

Journal of Evolutionary Biology @jevbio.bsky.social · Feb 25

How does the quality of pedigrees impact genetic studies? Based on genealogical data, bigger and deeper pedigrees improve precision, but even small errors skew results! Our work highlights the need for careful sensitivity analyses:

doi.org/10.1093/jeb/...

@wmawass.bsky.social and E. Milot

Assessing the impact of pedigree attributes on the validity of quantitative genetic parameter estimates

Abstract. Investigating the evolution of complex traits in nature requires accurate assessment of their genetic basis. Quantitative genetic (QG) modeling i

doi.org

6 4

Walid Mawass @wmawass.bsky.social · Feb 23

I truly don't understand the whole "report on your work, or get fired". These people were EMPLOYED! They didn't go into the government saying "I'll be doing this job then". They applied to a job ad that DESCRIBES their job duties and they were HIRED because someone judged them to be a good fit 🤦🏾‍♂️

Walid Mawass @wmawass.bsky.social · Feb 22

This is scary for the sheer illegality of these actions that the administration is taking and the jeopardy it puts people's life in! These employees can't even rely on their unions if the admin can just ignore unions outright!
www.reuters.com/world/us/us-...

US science agency reclassifies hundreds of workers as probationary, US lawmaker says

National Science Foundation administrators reclassified hundreds of employees from permanent to probationary status in violation of labor contracts, according to a U.S. lawmaker and agency employee.

www.reuters.com

1

Walid Mawass @wmawass.bsky.social · Feb 4

🥳My work on the reliability of pedigrees used in quantitative genetic estimations of the genetic basis of phenotypic trait is out now in @jevbio.bsky.social! It also serves as a good intro for the use of pedigrees to infer genetic signals of phenotypes in populations
academic.oup.com/jeb/advance-...

Assessing the impact of pedigree attributes on the validity of quantitative genetic parameter estimates

Abstract. Investigating the evolution of complex traits in nature requires accurate assessment of their genetic basis. Quantitative genetic (QG) modeling i

academic.oup.com

6 5

Walid Mawass @wmawass.bsky.social · Jan 12

This is good news! Even if not all demands were met, this is a clear demonstration of scientists ceizing the power to negotiate over compensation for their labor to the academic scientific enterprise. Add to it that the negotiations were with the government directly!
www.science.org/content/arti...

NIH postdocs, graduate students win union contract

Historic deal will boost researcher pay—if Congress provides funding

www.science.org

1 2

Walid Mawass @wmawass.bsky.social · Dec 28

Easy one! Vice(2018)...Doesn't even need explaining for those who have seen it!

Elizabeth Picciuto @epicciuto.bsky.social · Dec 27

What’s a good movie that makes a strong political or moral point?

Walid Mawass @wmawass.bsky.social · Dec 28

In my case, I would say it is "The Metamorphosis" by Franz Kafka.

David H. Montgomery @dhmontgomery.com · Dec 27

What are people's most ARCHETYPICAL novels? Not your FAVORITES per se, but the ones that best exemplify your tastes in novels, distilled into a single work?

Mine is probably Susanna Clarke's "Jonathan Strange & Mr Norrell."

2

Walid Mawass @wmawass.bsky.social · Dec 18

Has anyone done research using data from human pops? I am trying to decide on a choice of representative figure for my paper. Should I pick one of the type of data (a picture of a civil act used to recreate social genealogies) or a picture of possible subjects of the human population in question?

Walid Mawass @wmawass.bsky.social · Dec 12

It is without a doubt that academic research environments are shaping into a structured labor environment (grad researchers, postdoctoral researchers, staff scientists, principal investigators...). Therefore, it is no surprise that unionization is becoming prevalent.

Reposted by Walid Mawass

Joanna Masel @joannamasel.bsky.social · Dec 12

We identified protein domains in LUCA (Last Universal Common Ancestor). Their distinctive amino acid usage reveals the order amino acids were added to the genetic code, based mostly on size. Older proteins hint at earlier alternative codes. 1/15 @seekingluca.bsky.social www.pnas.org/doi/10.1073/...

Order of amino acid recruitment into the genetic code resolved by last universal common ancestor’s protein domains | PNAS

The current “consensus” order in which amino acids were added to the genetic code is based on potentially biased criteria, such as the absence of s...

www.pnas.org

12 110 250