A polyploid admixed origin of beer yeasts derived from European and Asian wine populations

Abstract

Strains of Saccharomyces cerevisiae used to make beer, bread and wine are genetically and phenotypically distinct from wild populations associated with trees. The origins of these domesticated populations are not always clear; human-associated migration and admixture with wild populations have had a strong impact on S. cerevisiae population structure. We examined the population genetic history of beer strains and find that ale strains and the S. cerevisiae portion of allotetraploid lager strains were derived from admixture between populations closely related to European grape wine strains and Asian rice wine strains. Similar to both lager and baking strains, ale strains are polyploid, providing them with a passive means of remaining isolated from other populations and providing us with a living relic of their ancestral hybridization. To reconstruct their polyploid origin we phased the 1 5 10 15 20 genomes of two ale strains and found ale haplotypes to both be recombinants between European and Asian alleles and to also contain novel alleles derived from extinct or as yet uncharacterized populations. We conclude that modern beer strains are the product of a historical melting pot of fermentation technology.

Spindle position dictates division site during asymmetric cell division in moss

“…During mitosis, endogenous TPX2-1, −2, and −4 proteins fused with Citrine (“Cit”) or mNeonGreen (“NG”) or SunTag (“ST”) in-frame at the C- or N- terminus, were enriched at the polar region of the spindle and phragmoplast, suggesting that they preferentially bind to MT minus ends (Figure 1C, Figure 1 – figure supplement 1, Supplemental Video 1). A similar localization has been reported for Arabidopsis TPX2 (Boruc et al, 2019; Vos et al, 2008). TPX2-5 was observed as dim speckles in the spindle and showed more uniform binding to phragmoplast MTs, suggesting that TPX2-5 might have an additional function (Figure 1C, Figure 1 – figure supplement 1E-F, Supplemental Video 1).…”

“…We identified five genes homologous to TPX2 in the P. patens genome using a BLAST search and named them TPX2-1 to -5 (Figure 1A). TPX2-1 to −4 proteins showed high similarity to canonical TPX2 in seed plants (e.g., A. thaliana and Orysa sativa ), whereas TPX2-5 appears to have lost the N-terminal Aurora-binding motif (Boruc et al, 2019; Tomaštíková et al, 2015; Vos et al, 2008), but retained the highly conserved C- terminal domains and, to a certain extent, γ-tubulin activation motifs (Alfaro-Aco et al, 2017) (Figure 1A, B). During mitosis, endogenous TPX2-1, −2, and −4 proteins fused with Citrine (“Cit”) or mNeonGreen (“NG”) or SunTag (“ST”) in-frame at the C- or N- terminus, were enriched at the polar region of the spindle and phragmoplast, suggesting that they preferentially bind to MT minus ends (Figure 1C, Figure 1 – figure supplement 1, Supplemental Video 1).…”

“…TPX2-5 was observed as dim speckles in the spindle and showed more uniform binding to phragmoplast MTs, suggesting that TPX2-5 might have an additional function (Figure 1C, Figure 1 – figure supplement 1E-F, Supplemental Video 1). Unlike TPX2 in animals or seed plants (Boruc et al, 2019; Vos et al, 2008), none of the TPX2 proteins of P. patens were sequestered in the nucleus during interphase (Figure 1 – figure supplement 2).…”

“…A previous study in A. thaliana , using a combination of knockout and cross-species antibody injection, suggested that TPX2 is an essential gene (Vos et al, 2008). However, these results were recently questioned when several viable AtTPX2 t-DNA insertion mutants were obtained (Boruc et al, 2019). In addition to canonical TPX2, several TPX2-like genes lacking one or more functional domains have been identified in A. thaliana .…”

“…In addition to canonical TPX2, several TPX2-like genes lacking one or more functional domains have been identified in A. thaliana . Among them, TPX2L3 lacks a C-terminal kinesin-binding motif but is strongly associated with Aurora kinases and is essential for embryogenesis (Boruc et al, 2019). However, the mechanism by which TPX2 contributes to spindle formation and MT amplification in plant cells remains unknown.…”