Supplementary Material for: Two Candidate Genes <i>(FTO</i> and <i>INSIG2)</i> for Fat Accumulation in Four Canids: Chromosome Mapping, Gene Polymorphisms and Association Studies of Body and Skin Weight of Red Foxes

Fat accumulation is a polygenic trait which has a significant impact on human health and animal production. Obesity is also an increasingly serious problem in dog breeding. The <i>FTO</i> and <i>INSIG2 </i>are considered as candidate genes associated with predisposition for human obesity. In this report we present a comparative genomic analysis of these 2 genes in 4 species belonging to the family Canidae – the dog and 3 species which are kept in captivity for fur production, i.e. red fox, arctic fox and Chinese raccoon dog. We cytogenetically mapped these 2 loci by FISH and compared the entire coding sequence of <i>INSIG2</i> and a fragment of the coding sequence of <i>FTO. </i>The <i>FTO</i> gene was assigned to the following chromosomes: CFA2q25 (dog), VVU2q21 (red fox), ALA8q25 (arctic fox) and NPP10q24–25 (Chinese raccoon dog), while the <i>INSIG2</i> was mapped to CFA19q17, VVU5p14, ALA24q15 and NPP9q22, respectively. Altogether, 29 SNPs were identified (16 in <i>INSIG2</i> and 13 in <i>FTO</i>) and among them 2 were missense substitutions in the dog (23C/T, Thr&gt;Met in the <i>FTO </i>gene and 40C/A, Arg&gt;Ser in <i>INSIG2</i>). The distribution of these 2 SNPs was studied in 14 dog breeds. Two synonymous SNPs, one in the <i>FTO</i> gene (–28T&gt;C in the 5′-flanking region) and one in the <i>INSIG2</i> (10175C&gt;T in intron 2), were used for the association studies in red foxes (n = 390) and suggestive evidence was observed for their association with body weight (<i>FTO</i>, p &lt; 0.08) and weight of raw skin (<i>INSIG2</i>, p &lt; 0.05). These associations indicate that both genes are potential candidates for growth or adipose tissue accumulation in canids. We also suggest that the 2 missense substitutions found in dogs should be studied in terms of genetic predisposition to obesity.

脂肪蓄积属于多基因性状，对人类健康与动物生产具有显著影响。犬繁育领域的肥胖问题也日益严峻。脂肪量和肥胖相关基因（FTO）以及胰岛素诱导基因2（INSIG2）被视为与人类肥胖易感性相关的候选基因。本研究对犬科（Canidae）4个物种的这2个基因开展比较基因组分析，受试物种包括家犬以及3种人工饲养的毛皮动物：赤狐、北极狐与貉。本研究通过荧光原位杂交（FISH）技术对这2个基因座进行细胞遗传学定位，并比对了INSIG2的完整编码序列以及FTO的部分编码序列。FTO基因的染色体定位结果如下：家犬CFA2q25、赤狐VVU2q21、北极狐ALA8q25以及貉NPP10q24–25；而INSIG2的定位结果依次为家犬CFA19q17、赤狐VVU5p14、北极狐ALA24q15以及貉NPP9q22。本研究共鉴定出29个单核苷酸多态性位点（SNPs），其中INSIG2上16个、FTO上13个；家犬中存在2个错义突变位点：FTO基因的23C/T（苏氨酸→甲硫氨酸）以及INSIG2的40C/A（精氨酸→丝氨酸）。研究人员对14个犬品种中这2个SNPs的分布情况进行了分析。本研究选取2个同义单核苷酸多态性位点开展赤狐（样本量n=390）的关联分析：1个位于FTO基因5'侧翼区的–28T>C位点，另1个位于INSIG2基因第2内含子的10175C>T位点；结果显示二者与赤狐体重（FTO，p<0.08）及生皮重量（INSIG2，p<0.05）存在潜在关联。上述关联结果表明，这2个基因均为犬科动物生长或脂肪蓄积相关的潜在候选基因。本研究同时提出，应针对家犬中发现的这2个错义突变位点开展肥胖遗传易感性相关研究。

搜集汇总

背景与挑战

背景概述

该数据集为补充材料，专注于FTO和INSIG2基因在四种犬科动物（狗、红狐、北极狐和貉）中的比较研究，包括基因的染色体定位、SNP多态性识别以及关联分析。研究发现，在红狐中，FTO和INSIG2基因的特定SNP与体重和皮肤重量存在潜在关联，提示这两个基因可能影响犬科动物的生长或脂肪积累过程。