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TWO GENETIC STREAMS. "It is often stated that sex chromosome evolution starts when one member of a chromosome pair acquires a sex-determination function, but this leaves out an important part of the evolution of genetic sex determination: two separate mutations, in order to produce genetically distinct females and males." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

MITOSIS DIFFERENCES exist between plants and animals. https://lnkd.in/gtXb3Gu View in LinkedIn

"A FEMALE SUPPRESSOR can evolve in a gynodioecious population, despite lowering the reproductive fitness of females, provided that its allele on the proto-Y is linked to the locus causing male sterility in females, which defines a proto-X chromosome." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

DNA REPLICATION. “Many plant cells also can continue DNA replication in the absence of mitosis, a process known as endoreduplication, causing polyploidy. Here, we review the molecular mechanisms that regulate cell division and endoreduplication and we discuss our understanding, albeit very limited, on how the cell cycle is integrated with plant development.” https://lnkd.in/gMU_Jac View in LinkedIn

SEPARATE EVOLUTION. "Plant or animal sex chromosomes that evolved recently from any of these ancestral states should contain a region with a cluster of sex-determining genes that are closely enough linked to allow separate sexes to evolve." https://lnkd.in/gCh5RAX View in LinkedIn

PLANT STATUS. "The most common ancestral state in plants is probably hermaphroditism, although dioecy can also evolve from monoecy (with developmentally well differentiated male and female flowers already having evolved)." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

MORPHOLOGY. "Studies of a wide diversity of animal and plant species have found differing degrees of genetic and structural differentiation between the two sex chromosomes." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

GENE EROSION. "The permanent heterozygosity of evolving Y or W chromosomes clearly favours the erosion of genes on these chromosomes, since the active counterparts on the X or Z chromosomes can maintain their functions, especially if dosage compensation evolves." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

PLANTS. "Most mating-type loci have no such asymmetry, all alleles generally being heterozygous in the diploid parts of the life cycle; in plants with the distylous form of heterostyly, however, one incompatibility type is heterozygous while the other is homozygous, similarly to sex chromosomes." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

FACTOID. "In diploid species one sex chromosome (the X or Z) is regularly present in two copies in one sex and undergoes crossing over, whereas the sex-specific chromosome or region is always heterozygous and nonrecombining." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn