13.3 Evo-Devo: Gene Duplication and Development

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Questions and Answers

Following a gene duplication event, which of the following scenarios would MOST LIKELY lead to the preservation and functional divergence of paralogs involved in developmental patterning?

One paralog acquiring loss-of-function mutations, effectively silencing its expression and leaving the other paralog to maintain the ancestral function.
Epigenetic modifications, such as DNA methylation and histone modification, leading to coordinated silencing of both paralogs exclusively in germline cells.
Paralogs experiencing distinct patterns of regulatory evolution, leading to differential expression in space and time during development, coupled with sequence divergence in the coding region. (correct)
Both paralogs undergoing purifying selection to conserve the original function, ensuring redundancy and robustness against deleterious mutations.

In the context of the Tbx4/5 gene duplication event in vertebrates, what distinguishes the evolutionary significance of this event?

The Tbx4/5 duplication facilitated the evolution of novel appendage development, with Tbx5 contributing to pectoral fin development. (correct)
The Tbx4/5 duplication resulted in the complete loss of function of both genes, leading to a vestigial developmental pathway.
The Tbx4/5 duplication led to complete functional redundancy, providing an evolutionary buffer against mutations in either gene.
The Tbx4/5 duplication represents a rare instance of convergent evolution, where two independent genes acquired identical developmental roles.

Which of the following scenarios BEST exemplifies the process of subfunctionalization following gene duplication, exemplified by the phytochrome B (PHYB) gene in plants?

PHYB1 primarily mediating phototropism (directional growth in response to light), while PHYB2 mainly regulates photosynthesis. (correct)
Both PHYB1 and PHYB2 undergoing frameshift mutations, leading to the production of non-functional proteins and the loss of light sensitivity.
Both PHYB1 and PHYB2 acquiring identical functions in light detection, resulting in a synergistic effect on photomorphogenesis.
PHYB1 specializing in far-red light detection in roots, while PHYB2 specializes in blue light detection in shoots.

Considering the evolutionary trajectory of the OEP16 gene family in land plants, which specific feature of OEP16S neofunctionalization is most directly linked to the diversification of flowering plants?

The acquisition of desiccation tolerance function by OEP16S during seed maturation, facilitating seed survival in diverse environments. (B) Signup and view all the answers

Assuming a novel gene duplication event occurs in a population of sexually reproducing organisms, which of the following factors would MOST significantly influence the long-term retention and divergence of the resulting paralogs?

The presence of pre-existing regulatory networks that can co-opt and modulate the expression of both paralogs in distinct spatial and temporal patterns. (C) Signup and view all the answers

In the context of Hox gene duplications and their impact on chordate body plan evolution, which of the following represents the MOST critical aspect of Hox gene function that underlies their evolutionary significance?

Their role as transcriptional regulators that specify regional identity along the anterior-posterior axis during embryonic development. (C) Signup and view all the answers

Suppose a researcher discovers a gene family in a newly sequenced genome of a deep-sea organism. Phylogenetic analysis reveals multiple paralogs with highly divergent protein sequences and expression patterns. Which of the following experimental approaches would provide the MOST compelling evidence for neofunctionalization within this gene family?

Conducting CRISPR-Cas9 mediated knockout experiments for each paralog individually and assessing the resulting phenotypic consequences on organismal fitness and behavior. (D) Signup and view all the answers

Considering the potential for gene duplication to drive evolutionary innovation, which of the following genomic features would MOST likely predispose a gene to undergo duplication and subsequent neofunctionalization?

Presence of multiple cis-regulatory modules (CRMs) with combinatorial control over gene expression, allowing for diversification of expression patterns following duplication. (B) Signup and view all the answers

A hypothetical signaling pathway crucial for cell fate determination relies on a single gene encoding a receptor tyrosine kinase (RTK). A gene duplication event occurs, resulting in two paralogs: RTK1 and RTK2. Which evolutionary outcome would MOST likely lead to the emergence of a novel cell fate specification mechanism?

RTK1 retains the original ligand-binding specificity, while RTK2 loses its extracellular domain and functions as an intracellular kinase, phosphorylating downstream targets independently of ligand stimulation. (A) Signup and view all the answers

You are studying the evolution of venom composition in a lineage of venomous snakes. You identify a gene family encoding a key toxin, with evidence of multiple duplication events throughout their evolutionary history. Which analytical approach would provide the MOST comprehensive understanding of the interplay between gene duplication and venom diversification?

Integrating genomic, transcriptomic, and proteomic data to reconstruct the evolutionary history of the toxin gene family, trace the emergence of novel toxin variants, and assess their functional consequences on venom activity and prey specificity. (A) Signup and view all the answers

Considering the role of gene duplication in the evolution of complex traits, which of the following scenarios would MOST effectively illustrate how duplicated genes can facilitate the evolution of phenotypic plasticity in response to environmental variation?

One paralog specializing in stress response under harsh conditions, while the other paralog maintains basal function under favorable conditions, enabling organisms to fine-tune their physiology according to environmental demands. (C) Signup and view all the answers

In the context of plant evo-devo, consider a duplicated gene involved in floral development. Which of the following evolutionary trajectories would be MOST likely to contribute to the diversification of floral morphology and pollination strategies?

One paralog acquiring novel cis-regulatory elements that restrict its expression to specific floral organs, leading to the evolution of specialized floral traits and enhanced pollinator attraction. (B) Signup and view all the answers

A population of insects experiences a whole-genome duplication event. Assuming that selection favors increased metabolic efficiency, which of the following adaptive scenarios would MOST likely result from the duplication?

Duplicated metabolic genes diverging in their regulatory sequences, leading to tissue-specific expression and optimized metabolic fluxes in different organs. (A) Signup and view all the answers

Which of the following evolutionary outcomes would MOST likely occur if a duplicated gene, originally involved in DNA repair, acquires a novel function in regulating immune cell activation?

The organism experiencing an enhanced ability to cope with both DNA damage and pathogen infections, providing a selective advantage in fluctuating environments. (D) Signup and view all the answers

How could the duplication of a gene encoding a transcription factor MOST effectively lead to the evolution of a novel developmental module?

By one paralog acquiring the ability to bind to novel DNA sequences, thereby co-opting new target genes into its regulatory network and creating a new developmental sub-circuit. (C) Signup and view all the answers

In a species of flowering plant, a gene involved in pigment production in petals is duplicated. Which of the following scenarios would MOST likely result in the evolution of novel color patterns that attract a wider range of pollinators?

One paralog acquiring the ability to produce a novel pigment with a distinct spectral reflectance, leading to the evolution of new color patterns that are attractive to different pollinator species. (B) Signup and view all the answers

Considering a gene duplication event involving a receptor protein crucial for hormone signaling, which evolutionary outcome would MOST effectively lead to the sensitization of a target tissue to lower hormone concentrations?

Both paralogs being expressed at significantly elevated levels, increasing the total receptor density and enhancing the target tissue's responsiveness to even minute amounts of hormone. (D) Signup and view all the answers

If a duplicated gene encoding a key enzyme in a metabolic pathway acquires a novel regulatory sequence that makes it responsive to a specific stress signal, what is the MOST likely adaptive consequence?

The organism gaining the ability to rapidly upregulate the metabolic pathway in response to the stress signal, enhancing its capacity to cope with the stressful condition. (A) Signup and view all the answers

How would the duplication of a gene encoding a chaperone protein MOST likely contribute to the evolvability of protein folding landscapes in a changing environment?

By one paralog acquiring the ability to recognize and stabilize misfolded proteins with new structural features, expanding the protein folding repertoire and increasing tolerance to environmental stressors. (A) Signup and view all the answers

In the context of evo-devo, which of the following evolutionary scenarios would BEST exemplify how gene duplication events can facilitate the decoupling of pleiotropic constraints, leading to the evolution of novel modular developmental programs?

One paralog specializing in one aspect of the ancestral pleiotropic function, while the other paralog specializes in another aspect, allowing for independent modulation of different developmental processes. (C) Signup and view all the answers

Flashcards

Gene Duplication

Multiple copies of the same gene (paralogs) within the genome.

Paralogs

Duplicate genes that have evolved to serve different or complementary functions.