Month: September 2022

INDEPENDENT BUT SIMILAR. "Sex-chromosomes in flowering plants have evolved independently but have a number of features in common. The X and Y chromosomes are always the largest chromosomes in the complement (and probably in the entire genus) and the Y chromosomes (or summed Y-multiples) are much larger than the X in all species except Humulus lupulus and Viscum." https://lnkd.in/gb3zS32 View in LinkedIn

PLOIDY EVENTS. "Although it is clear that the evolution of plant sex chromosomes is associated with large increases in the DNA amount, the reasons behind these increases and the types of sequence are not well understood." https://lnkd.in/gb3zS32 View in LinkedIn

VIRAL SEQUENCES AND SEX CHROMOSOMES. "In Rumex acetosa, sex chromosome specific repeated sequences have been described and the sex chromosomes appear to contain large amounts of retroviral and viral related sequences." https://lnkd.in/gb3zS32 View in LinkedIn

SEQUENCE DEGENERACY. "There is emerging evidence that plant sex chromosomes show some sequence degeneracy, as is the case in animal Y chromosomes, where the non-pairing segment of the Y chromosome largely lacks functional loci." https://lnkd.in/gb3zS32 View in LinkedIn

SUPPRESSION OF ONE SEX. "It is evident that the floral dichotomy shown by dioecious plant species results from modification during development of a perfect flower by suppression of one or other organ sets." https://lnkd.in/gb3zS32 View in LinkedIn

SUPPRESSION TIMING. "Comparison of male and female flowers from the various dioecious species reveals that the timing during flower development of the suppression event is enormously variable between species." https://lnkd.in/gb3zS32 View in LinkedIn

EARLY DIVERGENCE. "In a number of dioecious species, including Mercurialis annua, Cannabis sativa, Spinacia oleracea, and Humulus species, the divergence of the male and female developmental pathways occurs extremely early in floral development and the inappropriate organs are not initiated." https://lnkd.in/gb3zS32 View in LinkedIn

ABORTION OF ONE SEX. "In most species, however, both sets of sex organs are initiated and the inappropriate set of organs develops to some extent before abortion." https://lnkd.in/gb3zS32 View in LinkedIn

LATE DIVERGENCE. "In a small number of dioecious species such as Actinidia deliciosa and Asparagus officinalis, the developmental divergence occurs so late that male and female flowers are superficially indistinguishable from each other and from perfect flowers." https://lnkd.in/gb3zS32 View in LinkedIn

VARIETY OF SUPPRESSIONS. "This variation in timing and nature of suppression argues for the existence of a variety of different underlying mechanisms." https://lnkd.in/gb3zS32 View in LinkedIn