Parent and offspring genotypes influence gene expression in early life

Area of Science:

• Evolutionary biology
• Genomics
• Animal behavior

Background:

• Parental genetic variation can influence offspring fitness, but mechanisms in natural systems are poorly understood.
• White-throated sparrows (Zonotrichia albicollis) exhibit two genetic morphs (tan and white) with distinct mating patterns and parental care strategies.
• Disassortative mating results in tan male × white female (T × W) and white male × tan female (W × T) pairs, with differing care biases.

Purpose of the Study:

• To investigate the impact of parental genetic composition on nestling gene expression in white-throated sparrows.
• To identify specific genes and pathways affected by parental pair type and nestling morph.
• To explore the role of a specific supergene in regulating gene expression across tissues.

Main Methods:

• RNA sequencing (RNA-seq) was performed on whole blood samples from white-throated sparrow nestlings.
• Nestlings were sampled from nests representing both T × W and W × T pair types.
• Differential gene expression analysis and gene coexpression network analysis were conducted.

Main Results:

• Parental pair type significantly affected nestling gene expression, with 881 differentially expressed genes and seven coexpression modules identified.
• Nestlings in W × T nests (female-biased care) showed higher expression of genes involved in metabolism and stress response (e.g., SOD2, NR3C1).
• Nestlings also displayed morph-specific gene expression (92 differentially expressed genes), including immunity-related genes and genes within the supergene. The same regulatory hub genes were found in blood and adult brain tissues.

Conclusions:

• Parental genotypes and/or behaviors demonstrably influence nestling physiology and gene expression.
• The findings provide insights into the maintenance of the white-throated sparrow's genetic polymorphism.
• The identified regulatory hub genes within the supergene highlight its importance in structuring gene expression networks across different tissues.