Cheng & SteinrΓΌcken (2024, Annual Review of Genetics) review the population-genomic toolkit for inferring demography and detecting selection, spanning allele-frequency (PCA, F-statistics), site-frequency spectrum (SFS), linkage/IBD, coalescent-HMM, and machine-learning approaches, and closing on the central unsolved problem: joint inference of demography and genome-wide selection.
The review's strongest contribution is its explicit treatment of why neutrality assumptions fail. It shows that background selection (BGS), recent growth, and a smaller constant Ne can produce nearly identical pairwise diversity and SFS shapes, making model choice from Ο or SFS alone unreliable, and that demographic inference under false neutrality yields biased estimates .
Note: values are simulated by the review's authors, not observed data.
The review is comprehensive on modern coalescent-HMMs (PSMC, MSMC, SMC++, diCal2) and emerging ARG-based methods (Relate, CLUES, tree-imbalance statistics), which it argues are more robust to population-size changes than haplotype statistics. Machine-learning classifiers (ImaGene, diploS/HIC, SWIF(r), SURFDAWave) are covered but the review rightly cautions that their training simulations may not match real demographic/selection scenarios β an under-criticized external validity problem across the field.
Blind spots: (1) Coverage leans heavily on human genetics; validation status in non-model organisms is acknowledged but not resolved . (2) Since publication, SFS-based inference has advanced β Blockbuster now achieves deterministic inference at theoretical detection limits for recent changes, exceeding tools like fastsimcoal2 and Stairway Plot 2 the review emphasizes . (3) Population structure remains the dominant confounder for panmictic methods β shown empirically in mouse lemurs, where PSMC trajectories change qualitatively once structure is modeled .
Real applications expose practical gaps the review undersells. Reduced-representation data (RADseq, DArTseq) with ascertainment bias are widespread in conservation yet receive minimal treatment; ABC frameworks with explicit model-choice remain essential in such systems . Joint inference of demography and fitness effects is presented as emerging (Fitai, Johri et al.) but the review offers no practical workflow guidance for practitioners β a missed opportunity given the stated centrality of the problem.
The review is a synthesis, not a testable claim; its judgments are well-supported by simulation results it reproduces and by independent empirical comparisons. Confidence in its framing is high; the falsifiability question applies to its implied claim that joint inference frameworks can be built β Blockbuster's theoretical-limit results and structured-population corrections suggest partial progress the review predates.
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