An F₂ population of 239 chickens was obtained by an intercross between Nagoya (NAG), a native Japanese breed with low growth, and White Plymouth Rock (WPR), a Western breed with high growth. Using SNP markers obtained by restriction site‐associated DNA sequencing, genome‐wide QTL analysis was performed and it revealed three QTL for early postnatal growth in the F₂ population at genome‐wide 5% significance levels. The most highly significant QTL affecting body weights at 2–4 weeks of age and weight gains at 2–3 and 0–4 weeks was located on GGA4 between 34.0 and 65.6 Mb with LOD scores of 3.9–5.9 and it explained 4.9–9.9% of the total variance of the traits. The analysis provided evidence for significant QTL on GGA2 between 105.6 and 125.2 Mb (LOD = 4.6) and on GGA1 between 51.1 and 61.6 Mb (LOD = 4.0) which had effects on body weight at 3 weeks and body weight gain at 0–1 week respectively. These two genomic regions explained 6.6 and 6.9% of the phenotypic F₂ variance of the corresponding traits respectively. The allele derived from WPR at all QTL increased the corresponding traits. Neither sex‐specific nor epistatic QTL was detected. The results showed that the GGA4 QTL affecting multiple traits is a key locus responsible for early growth in our chicken cross, suggesting that this QTL may make a great contribution to genetic improvement of growth performance of the NAG breed with a low growth rate.

中文翻译：

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使用基于RAD测序的SNP标记对日本名古屋和白普利茅斯岩鸡品种杂交后代中的早期生长进行QTL分析

F ₂种群的239只鸡是通过名古屋（NAG）（一种生长缓慢的日本本土品种）和白普利茅斯岩（WPR）（一种高生长的西方品种）之间的杂交获得的。使用通过限制性位点相关的DNA测序获得的SNP标记，进行了全基因组QTL分析，发现了F ₂产后早期生长的三个QTL。全基因组显着性水平为5％的人群。影响2至4周龄体重和2至3至0至4周体重增加的最显着QTL位于34.0至65.6 Mb之间的GGA4上，LOD得分为3.9至5.9，解释了4.9至9.9％性状的总方差。该分析提供了证据，表明GGA2在105.6和125.2 Mb之间（LOD = 4.6）和GGA1在51.1和61.6 Mb之间（LOD = 4.0）有显着的QTL，这对3周体重和0-1周体重增加有影响分别。这两个基因组区域解释了表型F _2的6.6和6.9％相应性状的方差。从所有QTL的WPR衍生的等位基因均增加了相应的性状。未检测到性别特异性或上位性QTL。结果表明，影响多重性状的GGA4 QTL是导致我们的鸡杂交早期生长的关键位点，这表明该QTL可能为低生长率的NAG品种的生长性能的遗传改良做出了巨大贡献。