Search results
Results from the WOW.Com Content Network
Premeiotic, post meiotic, pre mitotic, or postmitotic events are all possibilities if imprints are created during male and female gametogenesis. However, if only one of the daughter cells receives parental imprints following mitosis, this would result in two functionally different female gametes or two functionally different sperm cells.
Living order of Lycophytes and ferns are taken from Christenhusz et al. 2011b [2] and Pteridophyte Phylogeny Group. [3] Living orders of Gymnosperms are added from Christenhusz et al. 2011a [ 4 ] while extinct orders are from Anderson, Anderson & Cleal 2007.
Interphase is the process through which a cell must go before mitosis, meiosis, and cytokinesis. [15] Interphase consists of three main phases: G 1, S, and G 2. G 1 is a time of growth for the cell where specialized cellular functions occur in order to prepare the cell for DNA replication. [16]
Some extinct early plants appear to be between the grade of organization of bryophytes and that of true vascular plants (eutracheophytes). Genera such as Horneophyton have water-conducting tissue more like that of mosses, but a different life-cycle in which the sporophyte is branched and more developed than the gametophyte.
In both plants and mammals there are two major mechanisms that are involved in establishing the imprint; these are DNA methylation and histone modifications. Recently, a new study [ 46 ] has suggested a novel inheritable imprinting mechanism in humans that would be specific of placental tissue and that is independent of DNA methylation (the ...
Plant embryonic development, also plant embryogenesis, is a process that occurs after the fertilization of an ovule to produce a fully developed plant embryo. This is a pertinent stage in the plant life cycle that is followed by dormancy and germination . [ 1 ]
The resulting meiospores develop into a gametophyte. Both the spores and the resulting gametophyte are haploid, meaning they only have one set of chromosomes. The mature gametophyte produces male or female gametes (or both) by mitosis. The fusion of male and female gametes produces a diploid zygote which develops into a new sporophyte.
The term "plants" is taken here to mean the Archaeplastida, i.e. the glaucophytes, red and green algae and land plants. Alternation of generations occurs in almost all multicellular red and green algae, both freshwater forms (such as Cladophora) and seaweeds (such as Ulva). In most, the generations are homomorphic (isomorphic) and free-living.