Ensuring faithful homologous recombination in allopolyploids is essential to maintain optimal fertility of the species. Variation in the ability to control aberrant pairing between homoeologous chromosomes in Brassica napus has been identified. The current study exploited the extremes of such variation to identify genetic factors that differentiate newly resynthesised B.
View Article and Find Full Text PDFThe heavy selection pressure due to intensive breeding of has created a narrow gene pool, limiting the ability to produce improved varieties through crosses between cultivars. One mechanism that has contributed to the adaptation of important agronomic traits in the allotetraploid has been chromosomal rearrangements resulting from homoeologous recombination between the constituent A and C diploid genomes. Determining the rate and distribution of such events in natural will assist efforts to understand and potentially manipulate this phenomenon.
View Article and Find Full Text PDFObjective: The study examined the effectiveness of a perinatal collaborative care intervention in moderating the effects of adverse neonatal birth events on risks of postpartum depressive symptoms and impaired functioning among women of lower socioeconomic status with antenatal depression.
Methods: A randomized controlled trial with blinded outcome assessments was conducted in ten public health centers, comparing MOMCare (choice of brief interpersonal psychotherapy, pharmacotherapy, or both) with intensive maternity support services (MSS-Plus). Participants had probable diagnoses of major depressive disorder or dysthymia during pregnancy.
We have developed a sequential procedure with fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) that enables us to distinguish between the A and C genomes in Brassica napus and to identify certain individual chromosomes or chromosome groups within a genome. Our modified GISH technique uses a repetitive sequence in addition to the whole genome in the blocking DNA, and it is effective on meiotic and mitotic cells present in the anther material that we use.
View Article and Find Full Text PDFBackground: Plants adopt different reproductive strategies as an adaptation to growth in a range of climates. In Arabidopsis thaliana FRIGIDA (FRI) confers a vernalization requirement and thus winter annual habit by increasing the expression of the MADS box transcriptional repressor FLOWERING LOCUS C (FLC). Variation at FRI plays a major role in A.
View Article and Find Full Text PDFDioecious Silene latifolia evolved heteromorphic sex chromosomes within the last ten million years, making it a species of choice for studies of the early stages of sex chromosome evolution in plants. About a dozen genes have been isolated from its sex chromosomes and basic genetic and deletion maps exist for the X and Y chromosomes. However, discrepancies between Y chromosome maps led to the proposal that individual Y chromosomes may differ in gene order.
View Article and Find Full Text PDFA small cluster of dioecious species in the plant genus Silene has evolved chromosomal sex determination and sex chromosomes relatively recently, within the last 10 million years (MY). Five dioecious Silene species (section Elisanthe) are very closely related (1-2 MY of divergence) and it was previously thought that all five have similar sex chromosomes. Here we demonstrate that in one of these species, Silene diclinis, the sex chromosomes have been significantly rearranged, resulting in the formation of neo-sex chromosomes.
View Article and Find Full Text PDFTransposable elements often accumulate in nonrecombining regions, such as Y chromosomes. Contrary to this trend, a new Silene retrotransposon described here, has spread recently all over the genome of plant Silene latifolia, except its Y chromosome. This coincided with the latest steps of sex chromosome evolution in this species.
View Article and Find Full Text PDFThe two genomes (A and C) of the allopolyploid Brassica napus have been clearly distinguished using genomic in situ hybridization (GISH) despite the fact that the two extant diploids, B. rapa (A, n = 10) and B. oleracea (C, n = 9), representing the progenitor genomes, are closely related.
View Article and Find Full Text PDFWe have assigned all nine linkage groups of a Brassica oleracea genetic map to each of the nine chromosomes of the karyotype derived from mitotic metaphase spreads of the B. oleracea var. alboglabra line A12DHd using FISH.
View Article and Find Full Text PDF