Identification of gynogenetic Megalobrama amblycephala induced by red crucian carp sperm and establishment of a new hypoxia tolerance strain

Previously, a homodiploid goldfish-like fish (2n = 100; GF-L) was spontaneously generated by self-crossing a homodiploid red crucian carp-like fish (2n = 100; RCC-L), which was in turn produced via the distant hybridization of female koi carp (Cyprinus carpio haematopterus, KOC, 2n = 100) and male blunt snout bream (Megalobrama amblycephala, BSB, 2n = 48). The phenotypes and genotypes of RCC-L and GF-L differed from those of the parental species but were similar to diploid red crucian carp (2n = 100; RCC) and goldfish (2n = 100; GF), respectively. We sequenced the complete mitochondrial DNAs (mtDNAs) of the KOC, BSB, RCC-L, GF-L, and subsequent generations produced by self-crossing [the self-mating offspring of RCC-L (RCC-L-F2) to the self-mating offspring of RCC-L-F2 (RCC-L-F3) and the self-mating offspring of GF-L (GF-L-F2)]. Paternal mtDNA fragments were stably embedded in the mtDNAs of both lineages, forming chimeric DNA fragments. In addition to these chimeras, several nucleotide positions in the RCC-L and GF-L lineages differed from the parental bases, and were instead identical with RCC and GF, respectively. Moreover, RCC-L and GF-L mtDNA organization and nucleotide composition were more similar to those of RCC and GF, respectively, compared to parental mtDNA. Finally, phylogenetic analyses indicated that RCC-L and GF-L clustered with RCC and GF, not with the parental species. The molecular dating time shows that the divergence time of KOC and GF was about 21.26 Mya [95% highest posterior density (HPD): 24.41–16.67 Mya], which fell within the period of recent. The heritable chimeric DNA fragments and mutant loci identified in the mtDNA of the RCC-L and GF-L lineages provided important evidence that hybridizations might lead to changes in the mtDNA and the subsequent generation of new lineages. Our findings also demonstrated for the first time that the paternal mtDNA was transmitted into the mtDNA of homodiploid lineages (RCC-L and GF-L), which provided evidence that paternal DNA plays a role in inherited mtDNA. These evolutionary analyses in mtDNA suggest that GF might have diverged from RCC after RCC diverged from koi carp.

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Hypoxia Tolerance, Nitric Oxide, and Nitrite: Lessons From Extreme Animals

Physiology ◽

10.1152/physiol.00051.2014 ◽

2015 ◽

Vol 30 (2) ◽

pp. 116-126 ◽

Cited By ~ 34

Author(s):

Angela Fago ◽

Frank B. Jensen

Keyword(s):

Nitric Oxide ◽

Marine Mammals ◽

Crucian Carp ◽

Physiological Responses ◽

Oxygen Deprivation ◽

Hypoxia Tolerance ◽

Carassius Carassius ◽

Slider Turtle ◽

Total Lack ◽

Crucian Carp Carassius Carassius

Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles ( Chrysemys picta and Trachemys scripta) and the crucian carp ( Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and–in air-breathing animals–redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance of NO and nitrite signaling in the adaptive response to hypoxia in vertebrate animals.

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