Pseudogenes, gene copies disabled by mutation, have long carried the junk DNA label. A recently published review in The Innovation Life makes the case that they have helped vertebrates adjust to new environments and also contribute to human illness. The human genome holds roughly 14,000 of them, and they are not scattered randomly. Current identification methods compare genes across species and screen homologous sequences for loss-of-function mutations, which helps distinguish true gene loss from assembly errors. A pattern keeps appearing: once a lineage moves into a new habitat, some genes become dispensable, and switching them off can be adaptive.
The authors gather examples across several traits. For immunity, whales and other marine mammals encounter bacterial communities unlike those on land. Cetaceans pseudogenized TLR5, a receptor that detects bacterial flagellin, and functional work shows that losing it dampens damaging inflammation and improves survival after infection. For vision, the naked mole-rat’s underground lifestyle relaxed selection on its eyes, so genes for phototransduction and retinal integrity picked up inactivating mutations and the eye became highly degenerate. Other subterranean mammals show the same pattern. For metabolism, hummingbirds depend on nectar to fuel hovering flight. Pseudogenization of FBP2, which encodes a muscle-specific gluconeogenic enzyme, boosts glycolytic flux, mitochondrial biogenesis, and respiratory capacity, sharpening carbohydrate use under extreme energy demands. For diet, the giant panda’s move from omnivore to near-exclusive bamboo eater coincided with loss of DUOX2. That change weakens thyroid-hormone synthesis and lowers basal metabolic rate, an economy that suits low-energy food. Loss of the umami receptor T1R1 may have accompanied the same shift.
In human disease, pseudogenes mostly act through duplicated copies that are still transcribed. PTENP1, a pseudogene of the tumor suppressor PTEN, sponges microRNAs and relieves repression of PTEN, which curbs cancer-cell proliferation. HBBP1 modulates TAL1 and eases beta-thalassemia, whereas transcripts such as TDGF1P3 drive tumor progression. Certain pseudogenes encode truncated peptides or serve as cis-regulatory DNA. Within disease networks, this class of elements can protect or cause harm.
The authors point out a gap. Pseudogene-derived regulatory RNAs are well documented in human disease but remain untested in adaptive evolution, largely because adaptation research has focused on unitary pseudogenes and non-model species are difficult to study experimentally. They suggest long-read RNA sequencing and CRISPR/Cas9 base editing, which can introduce or revert stop codons directly, as ways to test causal roles. They also note that convergent pseudogenization in distant species under similar pressures offers a useful model for how predictable evolutionary trajectories are.
Taken together, the review portrays pseudogenes as active participants in gene-expression networks rather than passive relics. In the right lineage at the right time, losing a gene can serve as a strategy.
The authors gather examples across several traits. For immunity, whales and other marine mammals encounter bacterial communities unlike those on land. Cetaceans pseudogenized TLR5, a receptor that detects bacterial flagellin, and functional work shows that losing it dampens damaging inflammation and improves survival after infection. For vision, the naked mole-rat’s underground lifestyle relaxed selection on its eyes, so genes for phototransduction and retinal integrity picked up inactivating mutations and the eye became highly degenerate. Other subterranean mammals show the same pattern. For metabolism, hummingbirds depend on nectar to fuel hovering flight. Pseudogenization of FBP2, which encodes a muscle-specific gluconeogenic enzyme, boosts glycolytic flux, mitochondrial biogenesis, and respiratory capacity, sharpening carbohydrate use under extreme energy demands. For diet, the giant panda’s move from omnivore to near-exclusive bamboo eater coincided with loss of DUOX2. That change weakens thyroid-hormone synthesis and lowers basal metabolic rate, an economy that suits low-energy food. Loss of the umami receptor T1R1 may have accompanied the same shift.
In human disease, pseudogenes mostly act through duplicated copies that are still transcribed. PTENP1, a pseudogene of the tumor suppressor PTEN, sponges microRNAs and relieves repression of PTEN, which curbs cancer-cell proliferation. HBBP1 modulates TAL1 and eases beta-thalassemia, whereas transcripts such as TDGF1P3 drive tumor progression. Certain pseudogenes encode truncated peptides or serve as cis-regulatory DNA. Within disease networks, this class of elements can protect or cause harm.
The authors point out a gap. Pseudogene-derived regulatory RNAs are well documented in human disease but remain untested in adaptive evolution, largely because adaptation research has focused on unitary pseudogenes and non-model species are difficult to study experimentally. They suggest long-read RNA sequencing and CRISPR/Cas9 base editing, which can introduce or revert stop codons directly, as ways to test causal roles. They also note that convergent pseudogenization in distant species under similar pressures offers a useful model for how predictable evolutionary trajectories are.
Taken together, the review portrays pseudogenes as active participants in gene-expression networks rather than passive relics. In the right lineage at the right time, losing a gene can serve as a strategy.