Université Paris Saclay, INRAE, AgroParisTech, GABI, 78350, Jouy-en-Josas, France.
Centre INRAE Val de Loire, UMR-BOA, SYSAAF, 37380, Nouzilly, France.
Genet Sel Evol. 2022 Aug 3;54(1):56. doi: 10.1186/s12711-022-00746-2.
On-going climate change will drastically modify agriculture in the future, with a need for more sustainable systems, in particular regarding animal production. In this context, genetic diversity is a key factor for adaptation to new conditions: local breeds likely harbor unique adaptive features and represent a key component of diversity to reach resilience. However, local breeds often suffer from small population sizes, which puts these valuable resources at risk of extinction. In chickens, population management programs were initiated a few decades ago in France, relying on a particular niche market that aims at promoting and protecting local breeds. We conducted a unique comprehensive study of 22 French local breeds, along with four commercial lines, to evaluate their genetic conservation status and the efficiency of the population management programs.
Using a 57K single nucleotide polymorphism (SNP) chip, we demonstrated that both the between- and within-breed genetic diversity levels are high in the French local chicken populations. Diversity is mainly structured according to the breeds' selection and history. Nevertheless, we observed a prominent sub-structuring of breeds according to farmers' practices in terms of exchange, leading to more or less isolated flocks. By analysing demographic parameters and molecular information, we showed that consistent management programs are efficient in conserving genetic diversity, since breeds that integrated such programs earlier had older inbreeding.
Management programs of French local chicken breeds have maintained their genetic diversity at a good level. We recommend that future programs sample as many individuals as possible, with emphasis on both males and females from the start, and focus on a quick and strong increase of population size while conserving as many families as possible. We also stress the usefulness of molecular tools to monitor small populations for which pedigrees are not always available. Finally, the breed appears to be an appropriate operational unit for the conservation of genetic diversity, even for local breeds, for which varieties, if present, could also be taken into account.
未来不断变化的气候将极大地改变农业，需要更可持续的系统，尤其是在动物生产方面。在这种情况下，遗传多样性是适应新条件的关键因素：地方品种可能具有独特的适应性特征，是实现弹性的多样性的关键组成部分。然而，地方品种通常面临着种群规模较小的问题，这使得这些宝贵的资源面临灭绝的风险。在鸡中，几十年前法国就启动了种群管理计划，该计划依赖于一个特定的利基市场，旨在促进和保护地方品种。我们对 22 个法国地方品种和 4 个商业品种进行了一项独特的综合研究，以评估它们的遗传保护状况和种群管理计划的效率。
使用 57K 个单核苷酸多态性（SNP）芯片，我们证明了法国本地鸡种群的种间和种内遗传多样性水平都很高。多样性主要根据品种的选择和历史来构建。然而，我们观察到根据农民在交换方面的做法，品种存在明显的亚结构，导致羊群或多或少地孤立。通过分析人口参数和分子信息，我们表明一致的管理计划能够有效地保护遗传多样性，因为更早纳入这些计划的品种具有更高的近交系数。
法国本地鸡品种的管理计划保持了其遗传多样性的良好水平。我们建议未来的计划尽可能多地抽样，从一开始就强调雄性和雌性，强调快速而强有力地增加种群数量，同时尽可能多地保留家族。我们还强调了分子工具在监测可能没有系谱的小种群方面的有用性。最后，即使对于地方品种，品种似乎也是保护遗传多样性的适当操作单位，对于那些存在品种的地方品种，也可以考虑将其纳入保护范围。
