Avian

Phenotypic Differences During Early Development in Gallus gallus

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Abstract

Phenotypic Differences During Early Development in Gallus gallusGallus gallus, commonly known as chickens, are a great model for studying developmental biology due to their in ovo embryonic development and the availability of high quality genomic resources. This project investigated genotype-phenotype relationships during early development in a fast-growth line of chicken (Broiler), and two distinct genetic crosses between fast-growth and slow-growth chicken lines (Fayoumi x Broiler, and Leghorn x Broiler). A total of 277 birds were sampled during necropsies at different timepoints. Chicks were sampled at embryonic days 10, 14, and 17 and post hatch days 0, 6, 21, and 35. Phenotypic data including egg weight, embryo weight, body weight, Pectoralis (P.) major muscle weight, heart weight, liver weight, and sex, were recorded during necropsy. P. major muscle, heart, and liver samples were also frozen for further analysis. P. major muscle samples were also embedded in OCT for cryosectioning to use for spatial transcriptomics. The sex of each embryo was determined through PCR and gel electrophoresis using DNA extracted from head tissue samples. For post-hatch chicks, sex at necropsy was confirmed by PCR and gel electrophoresis using DNA from blood samples collected at necropsy by a cardiac puncture. We hypothesized that Broiler, Fayoumi x Broiler and Leghorn x Broiler chicks would have different body weights at necropsy. A one-way ANOVA supported that each type of chicken differed in mean body weight (p = 0.0002). The Broiler line and the two genetic crosses also showed a significant difference in mean heart weight (p = 0.0108), liver weight (p = 0.0032), and P. major muscle weight (p = 0.0132). A linear regression was performed to test whether chick body weight was a good predictor of P. major muscle weight. It showed that chick body weight can accurately predict P. major muscle weight (R2 = 0.967, y = -3.226+0.045x, P< 0.001). After hatching, chicks were raised in separate isolators. To determine whether isolators had an effect on chick weight, a one-way ANOVA was performed. The results of the ANOVA (p = 0.9811) supported that isolator number did not affect chick weight. The phenotypic data provides the foundation for a comprehensive study that will soon be supplemented with transcriptomic data from RNA sequencing. Single-cell spatial transcriptomics will also be used to investigate gene expression and developmental mechanisms.

Keywords: 2026

How to Cite:

Hoffman, H., Abasht, B. & Lamont, S., (2026) “Phenotypic Differences During Early Development in Gallus gallus”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286087. doi: https://doi.org/10.31274/wcgalp.23849

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