Selection of large-grain wheat showing big grain sink potential and strong sink activity is becoming an important objective in breeding programs. In the previous study, we identified a QTL for thousand grain weight (TGW) on chromosome 1A using the Avocet/Chilero RIL population. A total of 347 high confidence genes with a physical length of 34.74 Mb were identified. Among these genes, TraesCS1A02G045300 and TraesCS1A02G058400 were associated with grain weight. The isolated TraesCS1A2G058400 genomic sequence was 24690 bp long and included 11 exons and 10 introns, is annotated with 28 domains and features, is associated with 491 variant alleles and maps to 9 oligo probes. Alignment of the TraesCS1A2G058400 sequences in Chinese spring showed a T/C substitution in the 6th exon (position 795) and 8th exon (position 1008), and three bases were missing at 1307 downstream of the start codon. Wheat (Triticum aestivum L.) protein sequences homologous to TraesCS1A02G058400 query sequences were downloaded from IWGSC RefSeq v1.1. via Ensembl Plants 47 following Blast searches. In total, 17 orthologous or paralogous sequences of homologs were selected from the Ensembl plant database. In the phylogenetic analysis, four wheat genes (TRITD1Av1G017620, TraesARI1A03G00020150, TraesJUL1A03G00020990 and TraesSYM1A03G00020600) were clustered with the TraesCS1A2G058400, which confirmed that they were TraesCS1A2G058400 orthologous genes. The identity of three homologous genes was 96.69% by multiple alignments, it thus should be a focus of subsequent research.