The distribution of male-transmitted and female-transmitted mitochondrial DNA types in somatic tissues of blue mussels: Implications for the operation of doubly uniparental inheritance of mitochondrial DNA

Genome ◽  
1998 ◽  
Vol 41 (6) ◽  
pp. 818-824 ◽  
Author(s):  
Manuel A Garrido-Ramos ◽  
Donald T Stewart ◽  
Brent W Sutherland ◽  
Eleftherios Zouros

We have examined the mitochondrial DNA (mtDNA) content of several somatic tissues from male and female individuals of the blue mussel, Mytilus edulis. As expected from the mode of doubly uniparental inheritance (DUI) of mtDNA that is characteristic of this genus, the dominant type of mtDNA in male gonads was the male-transmitted M type. In contrast, all male somatic tissues were dominated by the female-transmitted F type. The M type could occasionally be detected in one or another tissue of a few female individuals. The findings have several implications for the operation of doubly uniparental inheritance of mitochondrial DNA, among which the most important are (i) the M genome does not have an unconditional replicative advantage over the F genome, and (ii) in contrast to "masculinization" (the process by which an F molecule assumes the role of the M genome) "feminization" (the process by which an M molecule assumes the role of the F genome) might be a rare but not impossible phenomenon.Key words: mitochondrial DNA inheritance, mitochondrial DNA tissue distribution, blue mussels, gender-specific mtDNA, doubly uniparental inheritance of mtDNA, Mytilus.

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 883-894
Author(s):  
Liqin Cao ◽  
Ellen Kenchington ◽  
Eleftherios Zouros

Abstract In Mytilus, females carry predominantly maternal mitochondrial DNA (mtDNA) but males carry maternal mtDNA in their somatic tissues and paternal mtDNA in their gonads. This phenomenon, known as doubly uniparental inheritance (DUI) of mtDNA, presents a major departure from the uniparental transmission of organelle genomes. Eggs of Mytilus edulis from females that produce exclusively daughters and from females that produce mostly sons were fertilized with sperm stained with MitoTracker Green FM, allowing observation of sperm mitochondria in the embryo by epifluorescent and confocal microscopy. In embryos from females that produce only daughters, sperm mitochondria are randomly dispersed among blastomeres. In embryos from females that produce mostly sons, sperm mitochondria tend to aggregate and end up in one blastomere in the two- and four-cell stages. We postulate that the aggregate eventually ends up in the first germ cells, thus accounting for the presence of paternal mtDNA in the male gonad. This is the first evidence for different behaviors of sperm mitochondria in developing embryos that may explain the tight linkage between gender and inheritance of paternal mitochondrial DNA in species with DUI.


Genome ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 348-355 ◽  
Author(s):  
Anne C Dalziel ◽  
Donald T Stewart

Mytilus and other bivalves exhibit an unusual system of mitochondrial DNA (mtDNA) transmission termed doubly uniparental inheritance (DUI). Specifically, males transmit the mtDNA they have received from their fathers to their sons. Females transmit their mother's mtDNA to both sons and daughters. Males are normally heteroplasmic and females are normally homoplasmic, but not exclusively. This system is associated with an unusual pattern of molecular evolution. Male-transmitted mtDNA (M type) evolves faster than female-transmitted (F type) mtDNA. Relatively relaxed selection on the M type has been proposed as an explanation for this phenomenon. To further evaluate the selective forces acting upon the M-type genome, we used RT-PCR to determine where it is expressed. M-type mtDNA expression was detected in all gonad samples and in 50% of somatic tissues of males, and in a single female tissue. F-type mtDNA expression was detected in all female tissues, all male somatic tissues, and all but one male gonad sample. We argue that the expression of M-type mtDNA in male somatic and male gonad tissues has implications for the strength of selection acting upon it.Key words: gender-associated mitochondrial DNA, doubly uniparental inheritance of mtDNA, Mytilus edulis, molecular evolution.


Genetics ◽  
1996 ◽  
Vol 144 (1) ◽  
pp. 241-248 ◽  
Author(s):  
Paul D Ramon ◽  
Carol L Secor ◽  
Thomas J Hilbish

Abstract Blue mussels in the Mythilus edulis species complex have a doubly uniparental mode of mtDNA inheritance with separate maternal and paternal mtDNA lineages. Female mussels inherit their mtDNA solely from their mother, while males inherit mtDNA from both parents. In the male gonad the paternal mtDNA is preferentially replicated so that only paternal mtDNA is transmitted from fathers to sons. Hybridization is common among differentiated blue mussel taxa; whenever it involves M. trossulus, doubly uniparental mtDNA inheritance is disrupted. We have found high frequencies of males without and females with paternal mtDNA among hybrid mussels produced by interspecific matings between M. galloprovincialis and M. trossulus. In contrast, hybridization between M. galloprovincialis and M. edulis does not affect doubly uniparental inheritance, indicating a difference in the divergence of the mechanisms regulating mtDNA inheritance among the three blue mussel taxa. Our data indicate a high frequency of disrupted mtDNA transmission in F1 hybrids and suggest that two separate mechanisms, one regulating the transmission of paternal mtDNA to males and another inhibiting the establishment of paternal mtDNAin females, act to regulate doubly uniparental inheritance. We propose a model for the regulation of doubly uniparental inheritance that is consistent with these observations.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Cyril Dégletagne ◽  
Doris Abele ◽  
Gernot Glöckner ◽  
Benjamin Alric ◽  
Heike Gruber ◽  
...  

AbstractMetazoans normally possess a single lineage of mitochondria inherited from the mother (♀-type mitochondria) while paternal mitochondria are absent or eliminated in fertilized eggs. In doubly uniparental inheritance (DUI), which is specific to the bivalve clade including the ocean quahog, Arctica islandica, ♂-type mitochondria are retained in male gonads and, in a few species, small proportions of ♂-type mitochondria co-exist with ♀-type in somatic tissues. To the best of our knowledge, we report, for the first time in metazoan, the natural occurrence of male and female individuals with exclusively ♂-type mitochondria in somatic tissues of the bivalve A. islandica. Mitochondrial genomes differ by ~5.5% at DNA sequence level. Exclusive presence of ♂-type mitochondria affects mitochondrial complexes partially encoded by mitochondrial genes and leads to a sharp drop in respiratory capacity. Through a combination of whole mitochondrial genome sequencing and molecular assays (gene presence and expression), we demonstrate that 1) 11% of individuals of an Icelandic population appear homoplasmic for ♂-type mitochondria in somatic tissues, 2) ♂-type mitochondrial genes are transcribed and 3) individuals with ♂-type mitochondria in somatic cells lose 30% of their wild-type respiratory capacity. This mitochondrial pattern in A. islandica is a special case of DUI, highlighted in individuals from both sexes with functional consequences at cellular and conceivably whole animal level.


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