Incomplete maternal transmission of mitochondrial DNA in Drosophila
Kondo, R.; Satta, Y.; Matsuura, E.T.; Ishiwa, H.; Takahata, N.; Chigusa, S.I.
Genetics 126(3): 657-663
1990
ISSN/ISBN: 0016-6731 PMID: 2249764 Document Number: 364956
The possibility of incomplete maternal transmission of mitochondrial DNA (mtDNA) in Drosophila, previously suggested by the presence of heteroplasmy, was examined by intra- and interspecific backcrosses of Drosophila simulans and its closest relative, Drosophila mauritiana. mtDNAs of offspring in the crosses were characterized by Southern hybridization with two .alpha.-32P-labeled probes that are specific to paternal unit mtDNAs. This method could detect as little as 0.03% paternal mtDNA, if present, in a sample. Among 331 lines that had been backcrossed for ten generations, four lines from the interspecific cross D. simulans (female) .times. D. mauritiana (male) showed clear evidence for paternal leakage of mtDNA. In three of these the maternal type was completely replaced while the fourth was heteroplasmic. Since in this experiment the total number of fertilization is known to be 331 .times. 10 = 3310, the proportion of paternal mtDNA per fertilization was estimated as about 0.1%. The mechanisms and evolutionary significance for paternal leakage are discussed in light of this finding.