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CROSSOVER ZONES. "Many sex chromosome pairs have suppressed recombination extending over much of the Y, except for a small 'pseudoautosomal' region or regions (PAR) to which pairing and recombination are restricted. Since one crossover per chromosome arm is often required for disjunction, crossover rates are likely to be extremely high in these regions." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

CELL MIGRATION. “What mostly distinguishes animals from plants during development is motility and migration of cells. An example of migrating cells is a population of neural crest cells seen in all the vertebrates, which emigrate from the neural tube during early development.” https://lnkd.in/gVFjvM2 View in LinkedIn

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

GRADUAL OR DISCONTINUOUS. "Was recombination suppression in mammals a discontinuous process (due to successive inversions or translocations), or did it evolve gradually?" http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

NO CROSSOVER. "There is now evidence from several taxa (mammal, birds and plants) for more than a single event of cessation of recombination between X and Y chromosomes. The extent of DNA sequence divergence between homologous X/Y gene pairs of a single species has been found to vary greatly among genes, suggesting that different regions of the sex chromosomes have been nonrecombining for very different amounts of time, given that sequence divergence begins once crossing over between X and Y stops." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

SINGLE LOCUS. "By this type of process, a single locus takes control of sex determination, that is, derived states with a single sex-determining gene can evolve. Single locus sex determination, such as that of mammals, with a single Y-linked gene, SRY, controlling sex, might also be able to evolve directly, but no detailed model has yet been worked out to show how this could occur." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

NEW SEX GENES. "Another possible type of change is the emergence of a new sex-determining gene, epistatic to the previous sex determiner, so that the original genes no longer control sex development, as in the fly Musca domestica, and probably also in the medaka fish, Oryzias latipes. The sex-determining region of the fly, Megaselia scalaris, appears to transpose between chromosomes, creating new potential sex chromosomes." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn