Cytogenetic and Sequence Analyses of Mitochondrial DNA Insertions in Nuclear Chromosomes of Maize.
The transfer of mitochondrial DNA (mtDNA) into nuclear genomes is a regularly occurring process that has been observed in many species. Few studies, however, have focused on the variation of nuclear-mtDNA sequences (NUMTs) within a species. This study examined mtDNA insertions within chromosomes of a diverse set of Zea mays ssp. mays (maize) inbred lines by the use of fluorescence in situ hybridization. A relatively large NUMT on the long arm of chromosome 9 (9L) was identified at approximately the same position in four inbred lines (B73, M825, HP301, and Oh7B). Further examination of the similarly positioned 9L NUMT in two lines, B73 and M825, indicated that the large size of these sites is due to the presence of a majority of the mitochondrial genome; however, only portions of this NUMT (~252 kb total) were found in the publically available B73 nuclear sequence for chromosome 9. Fiber-fluorescence in situ hybridization analysis estimated the size of the B73 9L NUMT to be ~1.8 Mb and revealed that the NUMT is methylated. Two regions of mtDNA (2.4 kb and 3.3 kb) within the 9L NUMT are not present in the B73 mitochondrial NB genome; however, these 2.4-kb and 3.3-kb segments are present in other Zea mitochondrial genomes, including that of Zea mays ssp. parviglumis, a progenitor of domesticated maize.
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Ashley N
AN
Lough
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Kaitlyn M
KM
Faries
Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706.
Dal-Hoe
DH
Koo
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Abid
A
Hussain
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Leah M
LM
Roark
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Tiffany L
TL
Langewisch
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Teresa
T
Backes
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
Karl A G
KA
Kremling
Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706.
Jiming
J
Jiang
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211.
James A
JA
Birchler
Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211 NewtonK@missouri.edu.
Kathleen J
KJ
Newton
D032461:Chromosomes, Plant / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D016254:Mutagenesis, Insertional; D017422:Sequence Analysis, DNA; D003313:Zea mays / Q000235:genetics*
D004272:DNA, Mitochondrial
FISH; NUMT; diversity; variation