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"LACK OF RECOMBINATION among most genes carried on Y or W chromosomes reduces the ability of selection to fix favourable mutations and to prevent the fixation of deleterious ones, due to Hill–Robertson interference among completely linked loci (hitch-hiking processes)." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

PHYSICALLY DIFFERENT. "The X and Y (or Z and W) chromosomes are often morphologically distinguishable (heteromorphic), with the Y or W being largely heterochromatic and containing a high proportion of repetitive DNA." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

DEGENERATION. "Cessation of recombination between large parts or all of the sex chromosomes is the ultimate cause of the degeneration of Y or W chromosomes." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

EVOLUTION OF SEX CHROMOSOMES. "Structurally distinct sex chromosomes (X and Y) are the most familiar mode of genetic sex determination and have evolved independently in many different taxa." https://lnkd.in/ggJdV57 View in LinkedIn

FROG SEX CHROMOSOMES. "The existence of both male and female heterogametic individuals in one species is an extremely rare situation in nature, because some sex chromosome combinations produce offspring with sex ratios different from 1:1." http://www.pnas.org/content/112/34/E4752.full View in LinkedIn

FROGS. "As in most amphibians, sex chromosomes of the model species Xenopus tropicalis are homomorphic, complicating identification of the heterogametic sex. Using genetic approaches, we have proved the existence of three types of sex chromosomes (Y, W, and Z), defining three kinds of males (YZ, YW, and ZZ) and two kinds of females (ZW and WW)." https://lnkd.in/gvD548n View in LinkedIn

VARIABLE. "Two main sex chromosome systems can be found in vertebrates with genetic sex determination: XX/XY (in which males are heterogametic) and ZZ/ZW (with heterogametic females). Nevertheless, sex chromosomes are extraordinarily variable, and other combinations also can be found, ranging from female heterogamety with 00/0W or ZZ/Z0 sex chromosomes to male heterogamety with XX/X0 sex chromosomes. Furthermore, complex XY and ZW systems are possible when fusions, fissions, and translocations between sex chromosomes and autosomes take place (e.g., X1X2Y, XY1Y2, or Z1Z2W)." https://lnkd.in/gvD548n View in LinkedIn

HOMOLOGS. "In mammals, only a few X-linked genes have homologues on the Y chromosome, and several Y-linked genes are known that do not have homology to X-linked genes and have presumably been translocated to the Y from elsewhere; in D. melanogaster, all known Y-linked genes are in this latter category." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

1,516 mass shootings in 1,735 days: America's gun crisis – in one chart https://www.theguardian.com/us-news/ng-interactive/2017/oct/02/america-mass-shootings-gun-violence?CMP=Share_iOSApp_Other View in LinkedIn

ANCIENT VIRUSES AND SEX. “Our results highlight the role of TEs in the initial steps of differentiation and evolution of sex chromosomes.” (TE = transposable elements). https://lnkd.in/gMXukbs View in LinkedIn