scholarly journals Male-Dependent Doubly Uniparental Inheritance of Mitochondrial DNA and Female-Dependent Sex-Ratio in the Mussel Mytilus galloprovincialis

Genetics ◽  
1997 ◽  
Vol 145 (4) ◽  
pp. 1073-1082 ◽  
Author(s):  
Carlos Saavedra ◽  
María-Isabel Reyero ◽  
Eleftherios Zouros
Keyword(s):  
Mitochondrial Dna ◽  
Sex Ratio ◽  
Mytilus Galloprovincialis ◽  
Germ Line ◽  
Female Parent ◽  
Female Gonad ◽  
Uniparental Inheritance ◽  
Male Gonad ◽  
Doubly Uniparental Inheritance ◽  
Male Progeny

We have investigated sex ratio and mitochondrial DNA inheritance in pair-matings involving five female and five male individuals of the Mediterranean mussel Mytilus galloprovincialis. The percentage of male progeny varied widely among families and was found to be a characteristic of the female parent and independent of the male to which it was mated. Thus sex-ratio in Mytilus appears to be independent of the nuclear genotype of the sperm. With a few exceptions, doubly uniparental inheritance (DUI) of mtDNA was observed in all families fathered by four of the five males: female and male progeny contained the mother's mtDNA (the F genome), but males contained also the father's paternal mtDNA (the M genome). Two hermaphrodite individuals found among the progeny of these crosses contained the F mitochondrial genome in the female gonad and both the F and M genomes in the male gonad. All four families fathered by the fifth male showed the standard maternal inheritance (SMI) of animal mtDNA: both female and male progeny contained only the maternal mtDNA. These observations illustrate the intimate linkage between sex and mtDNA inheritance in species with DUI and suggest different major roles for each gender. We propose a model according to which development of a male gonad requires the presence in the early germ cells of an agent associated with sperm-derived mitochondria, these mitochondria are endowed with a paternally encoded replicative advantage through which they overcome their original minority in the fertilized egg and this advantage (and, therefore, the chance of an early entrance into the germ line) is countered by a maternally encoded egg factor.

Genetics of Mother-Dependent Sex Ratio in Blue Mussels (Mytilus spp.) and Implications for Doubly Uniparental Inheritance of Mitochondrial DNA

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1579-1588 ◽  
Author(s):  
Ellen Kenchington ◽  
Barry MacDonald ◽  
Liqin Cao ◽  
Defkalion Tsagkarakis ◽  
Eleftherios Zouros
Keyword(s):  
Mitochondrial Dna ◽  
Sex Ratio ◽  
Female Parent ◽  
Population Level ◽  
Uniparental Inheritance ◽  
Doubly Uniparental Inheritance ◽  
Ratio Bias ◽  
Sex Ratio Bias ◽  
Mitochondrial Genotype ◽  
Ratio Determination

Abstract Previous studies have shown that in most pair matings of Mytilus edulis, M. trossulus, and M. galloprovincialis there is a large sex-ratio bias in favor of either males or females. The degree of bias is a characteristic property of the female parent, as matings of the same female with different males produce the same sex ratio, but matings of the same male with different females produce different sex ratios. All three species possess the unusual feature of doubly uniparental inheritance of mitochondrial DNA (mtDNA); i.e., they contain two distinct types of mtDNA, one that is transmitted matrilinearly and one that is transmitted patrilinearly. This coupling of sex and mtDNA transmission raises the possibility that the mechanism of sex-ratio determination in mussels might be under the control of the mtDNA of the female parent. Here we present data from pedigreed crosses that confirm the previous observations that in mussel matings there is a strong sex-ratio bias and that the bias is under the control of the female parent. In addition, these data strongly suggest that this control is exercised by the mother's nuclear rather than mitochondrial genotype. Making use of these findings we develop a model of mother-dependent sex determination and use data from crosses involving wild females to test the model's predictions at the population level.

scholarly journals Differential Segregation Patterns of Sperm Mitochondria in Embryos of the Blue Mussel (Mytilus edulis)

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 883-894
Author(s):  
Liqin Cao ◽  
Ellen Kenchington ◽  
Eleftherios Zouros
Keyword(s):  
Mitochondrial Dna ◽  
Mytilus Edulis ◽  
Blue Mussel ◽  
Uniparental Inheritance ◽  
Male Gonad ◽  
Doubly Uniparental Inheritance ◽  
Organelle Genomes ◽  
Somatic Tissues ◽  
Tight Linkage ◽  
Mitotracker Green

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.

Tissue-specific expression of male-transmitted mitochondrial DNA and its implications for rates of molecular evolution in Mytilus mussels (Bivalvia: Mytilidae)

Genome ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 348-355 ◽  
Author(s):  
Anne C Dalziel ◽  
Donald T Stewart
Keyword(s):  
Mitochondrial Dna ◽  
Molecular Evolution ◽  
Uniparental Inheritance ◽  
Rt Pcr ◽  
Male Gonad ◽  
Doubly Uniparental Inheritance ◽  
Specific Expression ◽  
Somatic Tissues ◽  
Selective Forces ◽  
Rates Of Molecular Evolution

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.

scholarly journals Disruption of doubly uniparental inheritance of mitochondrial DNA in hybrid mussels (Mytilus edulis × M. galloprovincialis)

Heredity ◽  
2003 ◽  
Vol 91 (4) ◽  
pp. 354-360 ◽  
Author(s):  
A R Wood ◽  
G Turner ◽  
D O F Skibinski ◽  
A R Beaumont
Keyword(s):  
Mitochondrial Dna ◽  
Mytilus Edulis ◽  
Uniparental Inheritance ◽  
Doubly Uniparental Inheritance

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
Keyword(s):  
Mitochondrial Dna ◽  
Blue Mussel ◽  
Uniparental Inheritance ◽  
Doubly Uniparental Inheritance ◽  
Dominant Type ◽  
Blue Mussels ◽  
Somatic Tissues ◽  
Dna Types ◽  
M Genome

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.

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