Year: 2022

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

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

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

"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

"THE SHELTERING of recessive or partly recessive Y-linked deleterious mutations from selection due to their permanent heterozygosity” occurs. http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

NON-RECOMBINING. "The Chlamydomonas mating-type locus and incompatibility locus regions of some fungi with systems with two incompatibility types include large nonrecombining genome regions that differ in size, gene content and representation of transposable elements. The heteromorphic sex chromosomes of bryophytes, which are primarily haploid, represent a similar situation, although it is not yet known whether these homologous chromosome pairs show genetic degeneration." http://www.nature.com/hdy/journal/v95/n2/full/6800697a.html View in LinkedIn

Honey tests reveal global contamination by bee-harming pesticides https://www.theguardian.com/environment/2017/oct/05/honey-tests-reveal-global-contamination-by-bee-harming-pesticides?CMP=Share_iOSApp_Other View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend musing on the differences between animals and plants. Plants are distinguished from animals in a number of ways, but in particular, that where the individual starts and finishes in plants is far from clear. Plants have a distributed body plan that continues to develop during the entire life of the plant. View in LinkedIn

GERM CELL SET-ASIDES. “Imagine a textbook entitled Developmental Biology that focuses entirely on plants, mentioning animals only for their peculiar way of making germ cells by setting aside a group of precursor cells early in the embryo. The converse has been, and still is, common practice.” http://ac.els-cdn.com/0092867495900659/1-s2.0-0092867495900659-main.pdf?_tid=4d4ebb00-9318-11e7-86e1-00000aacb362&acdnat=1504712004_432302d5e397300b77a7d0a78440aca5 View in LinkedIn

“EMBRYOGENESIS in higher plants, therefore, serves (i) to specify meristems and the shoot-root body pattern, (ii) to differentiate the primary plant tissue types, (iii) to generate a specialized storage organ essential for seed germination and seedling development, and (iv) to enable the sporophyte to lie dormant until conditions are favorable for postembryonic development.” http://www.jstor.org/stable/pdf/2885440.pdf?seq=1#page_scan_tab_contents View in LinkedIn