Molecular detection and association of 12.1 kb deletion within the high mobility AT-hook 2 gene in the Netherlands dwarf rabbit (Oryctolagus Cuniculus)

Rabbits are mainly bred for human consumption and medical research. However, it has been recently showed that several rabbit breeds are also kept as pets for human leisure. The Netherlands dwarf rabbit is currently in the immense interest of many Vietnamese customers due to its personality and miniature stature. However, 12.1 kb deletion from position 44,709,089 to 44,721,236 bp in the high mobility AT-hook 2 (HMGA2) gene on chromosome 4 was identified as the structural variant causing dwarfism and altered craniofacial development in this breed. It has been documented that HMGA2 plays an important role in regulating growth and individuals with genotype HMGA2 del/del are fatal several days after birth. Despite the economically high value of the Netherlands dwarf rabbit, there has been no study on the genetic survey of lethal alleles in this breed in Vietnam. The aim of this study is to develop a fast and reliable method to screen the frequency of lethal alleles of HMGA2 in the South of Vietnam. Rabbit saliva was collected, and DNA extraction was followed. Multiplex polymerase chain reaction (PCR) with three primers was optimized and performed to detect the presence of 12.1 kb deletion within the HMGA2 sequence. Our data showed that the 12.1 kb deletion in the Netherlands dwarf rabbit population was detected by our optimized multiplex PCR. In 100 rabbit animals, 34 and 16 individuals were homozygous wild type (+/+) and homozygous mutant (del/del), respectively, while 50 rabbits were heterozygous. The frequency of HMGA2 lethal allele carrier was 66% (66/100 individuals). Our results indicated that we successfully developed a fast, accurate multiplex PCR to detect carrier individuals. Verification of the genotypes was followed by sequencing. We recommend implementing our multiplex PCR procedure in genetic selection for carrier and homozygous wild-type animals in the mating scheme to prevent the lethality of the rabbit offspring. Additionally, awareness should be raised among rabbit breeders to monitor the genetic makeup of the Netherlands dwarf rabbit populations. However, due to the limitation of the sample size, more samples should be taken in future studies to obtain the genetic frequency of the HMGA2 lethal allele more accurately.