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Spontaneous polyploidy, gynogenesis and androgenesis in second generation ( F 2 ) koi Cyprinus carpio × goldfish Carassius auratus hybrids
Author(s) -
Delomas T. A.,
Gomelsky B.,
Anil A.,
Schneider K. J.,
Warner J. L.
Publication year - 2017
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/jfb.13157
Subject(s) - biology , cyprinus , ploidy , hybrid , backcrossing , genetics , genotype , offspring , common carp , carp , carassius auratus , microsatellite , sperm , sex ratio , fish <actinopterygii> , zoology , andrology , allele , gene , fishery , botany , pregnancy , medicine , population , demography , sociology
The objective of this study was to characterize the genetics of second generation ( F 2 ) koi Cyprinus carpio × goldfish Carassius auratus hybrids. Spermatozoa produced by a novel, fertile F 1 male were found to be diploid by flow‐cytometric analysis. Backcross ( F 1 female × C. carpio male and C. carpio female × F 1 male) juveniles were triploid, confirming that female and male F 1 hybrids both produced diploid gametes. The vast majority of surviving F 2 juveniles was diploid and small proportions were aneuploid (2·1 n –2·3 n and 3·1 n –3·9 n ), triploid (3 n ) and tetraploid (4 n ). Microsatellite genotyping showed that F 2 diploids repeated either the complete maternal or the complete paternal genotype. Fish with the maternal genotype were female and fish with the paternal genotype were male. This demonstrates that F 2 diploids were the result of spontaneous gynogenesis and spontaneous androgenesis. Analysis of microsatellite inheritance and the sex ratio in F 2 crosses showed that spontaneous gynogenesis and androgenesis did not always occur in equal proportions. One cross was found to have an approximate equal number of androgenetic and gynogenetic offspring while in several other crosses spontaneous androgenesis was found to occur more frequently than spontaneous gynogenesis.