International Journal of Marine Science, 2025, Vol.15, No.3, 167-178 http://www.aquapublisher.com/index.php/ijms 167 CaseStudy Open Access Genetic Basis and Molecular Mechanisms of Trait Variation in the Domestication of Abalone Fei Zhao1,ManmanLi 2 1 Institute of Life Science, Jiyang College of Zhejiang A&F University, Zhuji, 311800, Zhejiang, China 2 Hainan Institute of Biotechnology, Haikou, 570206, Hainan, China Corresponding author: manman.li@hibio.org International Journal of Marine Science, 2025, Vol.15, No.3, doi: 10.5376/ijms.2025.15.0015 Received: 30 Apr., 2025 Accepted: 08 Jun., 2025 Published: 28 Jun., 2025 Copyright © 2025 Zhao and Li, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Zhao F., and Li M.M., 2025, Genetic basis and molecular mechanisms of trait variation in the domestication of abalone, International Journal of Marine Science, 15(3): 167-178 (doi: 10.5376/ijms.2025.15.0015) Abstract Abalone is an important seafood shellfish, but it faces bottlenecks such as slow growth, poor stress resistance and limited reproduction efficiency during artificial domestication and breeding. This study reviews the rules of phenotypic trait variation during abalone domestication and deeply analyzes its genetic basis and molecular mechanism. In terms of traits such as growth, stress resistance and reproduction, the domesticated abalone population showed significant variations, and some excellent traits were strengthened by artificial selection. The application of modern molecular breeding technology has promoted the research on genetic improvement of abalone. Multi-omics such as genome sequencing, QTL localization, candidate gene screening, transcriptome and proteome have revealed important genes and signaling pathways that affect the trait of abalone. For example, IGF and mTOR are involved in regulating growth, NF-κB and HSP networks mediate immune resistance, and gonad development is regulated by specific genes. We also discuss the latest attempts and challenges of RNA interference and CRISPR/Cas9 gene editing in abalone functional gene verification. Through cases such as the cultivation of Japanese Ezo abalone (Haliotis discus hannai) disease-resistant strains, South African abalone (Haliotis midae) multi-generation breeding, and Hainan hybrid abalone multi-omics analysis, the direction of innovation in the abalone seed industry is expected. Research believes that integrating traditional breeding and molecular biology methods is expected to accelerate the genetic improvement of abalone, cultivate new varieties with fast growth and strong resistance to stress, and promote the sustainable development of abalone breeding industry. Keywords Abalone; Trait variation; Genetic basis; Multiomic analysis; Gene editing 1 Introduction Abalone (Haliotis) has been known as the "crown of sea treasures" since ancient times because of its delicious meat and high nutritional value. It is an important economic species in coastal fishery and aquaculture. In recent years, with the decline of marine fishing resources, the abalone breeding industry has developed rapidly. China has become the world's largest abalone breeding country, with an annual output of more than 200,000 tons, accounting for more than 90% of the world (Zhou et al., 2023). However, problems such as long growth cycle of abalone (usually more than 2 years of commodity specifications), prone to outbreaks in high temperature and hypoxia seasons, and germplasm degradation are becoming increasingly prominent. The deterioration of traits caused by improper inbreeding and breeding also brings hidden dangers to the industry. In order to meet the industry's demand for excellent abalone varieties, it is urgent to carry out abalone genetic breeding research to improve key traits such as growth rate, stress resistance and fertility (Ke et al., 2016). Artificial domestication refers to the process in which wild groups are raised and bred through artificial environments, gradually adapting to and producing genetic changes. During the abalone domestication process, phenotypic traits undergo significant variations: on the one hand, excellent traits accumulate under artificial selection, such as faster growth, larger individuals and stronger heat and disease resistance, which appear one after another (Wang et al., 2024); on the other hand, adverse traits may also appear due to inbredness, such as the decrease in stress resistance caused by germplasm degeneration. Studies have shown that there are genetic differences between abalones in different domesticated generations from wild populations in terms of growth and survival traits.
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