# Genome-Wide Identification of Genomic Regions Associated with Body Weight and Morphometric Traits in Awassi Sheep

## TL;DR

This study identifies genetic regions linked to body weight and shape in Awassi sheep, offering insights for improving meat production through DNA-based breeding.

## Contribution

The study provides a genome-wide analysis of body traits in Iraqi Awassi sheep, identifying novel genomic regions and candidate genes for marker-assisted selection.

## Key findings

- Multiple genomic regions were found to be significantly associated with body weight and morphometric traits in Awassi sheep.
- Candidate genes like DST, CFAP299, ADAMTS8, and CPEB2 were identified as potentially influencing body conformation and growth.
- Functional enrichment analyses revealed pathways related to cell-matrix interactions and gene regulation affecting body traits.

## Abstract

Improving growth and body shape is an important goal in Awassi sheep because heavier and better-conformed animals can increase meat production and farm income. In Iraqi Awassi sheep, however, the genomic regions that influence differences in growth and body measurements are not well described, which limits the use of DNA information in breeding. This study aimed to identify genomic regions associated with five key traits in 315 one-year-old Iraqi Awassi sheep: body length, chest depth, chest circumference, shoulder height, and body weight. We measured these traits in animals raised under local farm conditions and examined thousands of DNA markers across the genome. We found several genomic regions that were clearly associated with variation in these traits and highlighted nearby genes that may affect tissue growth, body structure, and cell attachment and interactions with surrounding support tissues. Overall, the results provide a clearer picture of the genetic factors underlying growth and body conformation in Iraqi Awassi sheep. These findings can support the development of practical DNA-based selection tools to help breeders choose animals with better growth potential, improving productivity and supporting more efficient and sustainable sheep production.

In this study, we investigated the genomic basis of key body measurement and weight traits in Iraqi Awassi sheep using a multi-locus genome-wide association approach. A total of 315 yearling animals were phenotyped for body length, chest depth, heart girth, withers height, and body weight, and genotyped using the Ovine 50K SNP BeadChip. Genome-wide association analyses were performed within the BLUPmrMLM framework to improve the detection of loci with moderate-to-small effects. Significant associations were identified using an LOD-based threshold (LOD ≥ 5), followed by positional annotation of nearby genes and functional enrichment analyses to infer their potential biological relevance. Multiple genomic regions were associated with the evaluated traits. Among the most biologically plausible candidate genes were DST and CFAP299 for body length, ADAMTS8 for chest depth, ZFPM1 and OST4 for heart girth, CPEB2 for body weight, and ITGBL1, RBMS3, and THSD7B for withers height. Functional enrichment analyses indicated the involvement of pathways related to integrin-mediated signaling, focal adhesion and integrin complexes, extracellular matrix organization, and post-transcriptional regulation, suggesting coordinated effects of cell–matrix interactions and gene-expression regulation on body size and conformation. Overall, these findings refine the genomic landscape underlying body weight and morphometric variation in Awassi sheep and provide a focused set of loci for future validation and possible application in marker-assisted and genomic selection programs.