Visitors to China can hardly miss the quintessential ponds of goldfish that dot the landscapes temples, public parks, and buildings across the country. Indeed, goldfish have been an aesthetic component of religious landscaping in China at least since the first written records of their use in the Tsin Dynasty (265–419 A.D.), well before the fish was transferred to Japan in the sixteenth century and Europe in the eighteenth. But few know where goldfish originated. The historical records, though informative on the usage of goldfish as a decoration, offer no guidance as to the breeding of the fish, nor to exactly where or when they were first domesticated.
Researchers have attempted to explain the origin of goldfish in terms of their taxonomy. In the mid-eighteenth century, Linneaus originally named the goldfish Cyprinus auratus because of its morphological similarity to the common carp, Cyprinus carpio; later both Cyprinus auratus and Cyprinus carpio were transferred to the genus Carassius. Since then, others have tried grouping it by other morphological characteristics, like body shape, fin-style, or eye-shape, giving rise to three different taxonomic schemes, none of which adequately explaining the history of goldfish domestication
Taxonomy is far more informative, and accurate, when based on evolutionary history. The three existing taxonomies other researchers have created focus only on human-selected morphological characteristics that came about through domestication, and offer little in explaining the actual origins of the goldfish. Shu-Yan Wang of the School of Life Sciences, University of Science and Technology of China in Heifi and Ya-Ping Zhang’s lab at the Kunming Institute of Zoology (KIZ), part of the State Key Laboratory of Genetic Resources and Evolution, decided to go “fishing” for the truth.
By analyzing the nucleotide sequences from part of the control region (CR) and the entire
cytochrome b (Cytb) mitochondrial DNA genes of 234 goldfish around China and Japan and testing these against traditional morphological characteristics used determining the taxonomy of goldfish taxonomy–body shape, dorsal fin, eye shape, and tailfin–they were able to identify those that better correspond to the actual evolutionary history of the goldfish. Through their analyses, Wang’s team found that the haplotypes of goldfish are rooted in two sublineages, C5 and C6, that contain haplotypes of native C. a. auratus from southern China. Likewise, the results of genetic analysis actually showed that eye-shape may be the least informative character for grouping goldfish with respect to their evolutionary history.
The evidence Wang’s team collected led them to conclude that the Chinese goldfish has a matrilineal origin from native southern Chinese C. a. auratus, especially the lineages
from the lower Yangtze River. Anthropogenic selection of the native Carassius seems to have eliminated aesthetically unappealing goldfish and this action appeared to be responsible for the stepwise decrease in genetic diversity of domesticated goldfish, similar to the process that has been observed in other species domesticated in China like pigs, rice, and maize.
Wang’s findings mark not only an important scientific accomplishment in untangling the complicated history of the goldfish’s domestication and clarifying some of the inconsistent taxonomic definitions, but a breakthrough in early Chinese history. Their findings demonstrate how goldfish were not descended from the Gibel Carp of Northern China in the Amur River, which runs through Eurasia, but were instead domesticated in Southern China, consistent with the historical records that imply domestication in Hangzhou and Jiaxin, Zhejiang. This pairing of scientific data and historical records offers unprecedented insight that the available historical records have not been able to offer to date on the accomplishments of early Chinese civilization that were later exported to Japan and later Europe and the Americas.
The complete study “Origin of Chinese Goldfish and Sequential Loss of Genetic Diversity Accompanies New Breeds” was recently published in PLoS One 8(3), can be read free online at http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059571.
(By Andrew Willden)
