Year: 2022

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

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

"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

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

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

GENE ACCUMULATION. "The Y chromosome is thus expected to accumulate genes beneficial for male functions, confining them to males, and male attractiveness genes in guppies are indeed often partially Y-linked. Once such genes have accumulated, there is a selective advantage to suppressing crossing over between them and the sex-determining regions of the proto-sex chromosomes." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

FAVORED LINKAGE. "Translocations or centric fusions involving an autosome and a sex chromosome could also create linkage between sexually antagonistic genes and the sex chromosomes, and hence be favoured by natural selection." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

SUPPRESSION. "In addition to the creation of linkage between genes that were formerly on separate chromosomes, such rearrangements often reduce or suppress crossing over in the regions around the breakpoints in heterozygotes with the standard arrangement." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

NEO-SEX CHROMOSOME. "Chromosomes newly subjected to a sex chromosomal inheritance pattern in this way are called 'neo-sex chromosomes'. A classic example is the Drosophila miranda Y-autosome fusion, which involves the homologue of the third chromosome of its close relative D. pseudoobscura." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

"NEO-SEX chromosome systems are known in many plants and animals, including XY1Y2 in the plant Rumex acetosa, and multiple sex chromosomes due to translocations in African misteltoes, termites, African pygmy mice and monotremes." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn