The effect of H-2 region and genetic background on hormone-induced ovulation rate, puberty, and follicular number in mice.

We have examined the effects of major histocompatibility (H-2) haplotypes and genetic background (all loci other than the H-2 region) on hormone-induced ovulation rate in congenic strains of mice. In comparison with the H-2a haplotype, the H-2b haplotype increased hormone-induced ovulation rate 92% on the A/J (A) genetic background. However, H-2 haplotype did not affect hormone-induced ovulation rate on the C57BL/10J (C57) genetic background.

Plant mitochondrial DNA evolves rapidly in structure, but slowly in sequence.

We examined the tempo and mode of mitochondrial DNA (mtDNA) evolution in six species of crucifers from two genera, Brassica and Raphanus. The six mtDNAs have undergone numerous internal rearrangements and therefore differ dramatically with respect to the sizes of their subgenomic circular chromosomes. Between 3 and 14 inversions must be postulated to account for the structural differences found between any two species.

Unusual structure of geranium chloroplast DNA: A triple-sized inverted repeat, extensive gene duplications, multiple inversions, and two repeat families.

Physical and gene mapping studies reveal that chloroplast DNA from geranium (Pelargonium hortorum) has sustained a number of extensive duplications and inversions, resulting in a genome arrangement radically unlike that of other plants. At 217 kilobases in size, the circular chromosome is about 50% larger than the typical land plant chloroplast genome and is by far the largest described to date, to our knowledge. Most of this extra size can be accounted for by a 76-kilobase inverted duplication, three times larger than the normal chloroplast DNA inverted repeat.

Unicircular structure of the Brassica hirta mitochondrial genome.

Restriction mapping studies reveal that the mitochondrial genome of white mustard (Brassica hirta) exists in the form of a single circular 208 kb chromosome. The B. hirta genome has only one copy of the two sequences which, in several related Brassica species, are duplicated and undergo intramolecular recombination.

Tricircular mitochondrial genomes of Brassica and Raphanus: reversal of repeat configurations by inversion.

We constructed complete physical maps of the tripartite mitochondrial genomes of two Crucifers, Brassica nigra (black mustard) and Raphanus sativa (radish). Both genomes contain two copies of a direct repeat engaged in intragenomic recombination. The outcome of this recombination in black mustard is to interconvert a 231 kb master chromosome with two subgenomic circles of 135 kb and 96 kb.