Month: September 2022

TWO HOUSES. “Roughly 6% of all angiosperms are dioecious but the genes controlling sex determination and their organization on sex chromosomes in diecious plants are largely unknown.” https://lnkd.in/gKA5C8N View in LinkedIn

ONE HOUSE TO TWO HOUSES. “As had been demonstrated earlier in maize, fixation of a null mutation at one locus in a monecious population set the stage for segregation of a null mutation at a second locus, resulting in dioecy and single-gene sex determination.” https://lnkd.in/gKA5C8N View in LinkedIn

PRECEDENT DETAILS. “The experimental one-gene sex determination systems described for melon and maize, involve mutations in two genes, but it is the segregation of a single functional gene that ultimately determines sex.” https://lnkd.in/gKA5C8N View in LinkedIn

ASPARAGUS LANDSCAPE. “The genus Asparagus includes just over 200 species, the vast majority of which are hermaphrodites. Previous work has shown that dioecy arose within a single clade in the Asparagus phylogeny.” https://lnkd.in/gKA5C8N View in LinkedIn

TWO EVENTS. “Phylogenetic analyses suggest that dioecy evolved once or potentially twice within a single clade in the Asparagus phylogeny, coincident with increases in genome size and repetitive DNA content, as well as a range expansion from southern Africa into northern Africa and Europe.” https://lnkd.in/gKA5C8N View in LinkedIn

GENE DOUBLING. “The haploid genome size of diecious Asparagus species has been characterized as being nearly double that of hermaphroditic species.” https://lnkd.in/gKA5C8N View in LinkedIn

GENE DOUBLING. “The haploid genome size of diecious Asparagus species has been characterized as being nearly double that of hermaphroditic species.” https://lnkd.in/gKA5C8N View in LinkedIn

VIRAL REMAINS OR GENOME DUPLICATIONS. “Earlier work suggested that the increased genome size may have been due to increased rates of retrotransposon accumulation in diecious Asparagus genomes, but synteny analysis of the reference genome assembly revealed evidence for at least two ancient whole genome duplications.” https://lnkd.in/gKA5C8N View in LinkedIn

RECENT DIOECY. “In garden asparagus, X and Y chromosomes are cytologically homomorphic, and YY “supermale” genotypes are viable and produce fertile pollen, suggesting a recent origin of dioecy and sex chromosomes in the genus.” https://lnkd.in/gKA5C8N View in LinkedIn

TWO GENE SYSTEM. “Male and female organs are both initiated in developing garden asparagus flower buds, and differences in the timing of cessation of male pistil development and degeneration of female anthers are suggestive of a two-gene sex determination system.” https://lnkd.in/gKA5C8N View in LinkedIn