DOI: 10.5061/dryad.pzgmsbd1h
title: Data from: The arduous path to obligate asexuality in <em>Daphnia</em>

description: Evolutionary transitions to asexuality are often studied by comparing
 asexuals found in nature with closely related sexuals. Yet, asexuals
 sampled in nature may represent only the most successful lineages and
 therefore provide limited information about the average properties of
 newly emerging asexuals. These properties are crucial in determining the
 success of asexual lineages and hence the frequency with which transitions
 to asexual life cycles evolve. Here, we generate new asexual lineages of f
 Daphnia pulex through contagious asexuality, in which rare males from
 obligate asexual lineages transmit asexuality to new lineages by mating
 with sexual females. Unlike asexuals found in nature, most new lineages
 were capable of both sexual and asexual reproduction (facultative
 asexuality) and produced non-identical (i.e., non-clonal) daughters when
 reproducing asexually. They also showed reduced fertility compared to
 natural asexuals, especially when reproducing asexually, which is expected
 to reduce the success rate of sex-asex transitions in nature. Taken
 together, these results suggest that creating new asexual lineages by
 contagion is more complex than previously thought and may result in
 diverse, non-clonal offspring, on which subsequent selection can act. If
 general, such initial fitness valleys associated with sex-asex transitions
 may be key to resolving the evolutionary “paradox of sex”.
description: # Data from: The arduous path to obligate asexuality in *Daphnia* Dataset
 DOI: [10.5061/dryad.pzgmsbd1h](10.5061/dryad.pzgmsbd1h) ## Description of
 the data and file structure To obtain a quantitative estimate of the
 proportions of asexually produced F2s, mixed, and sexual F1s, as well as
 to test for a possible difference between male-producing (MP) vs. non-male
 producing (NMP) offspring, we used a likelihood model approach. This
 allowed us to combine the information from several technically difficult
 to obtain and therefore somewhat disparate data sets, but all from the
 main cross (TEX-114 x STM-2). The models used data on fill rates in
 presence and absence of males (in NMP F1s and, for the estimation of the
 sterility rate also in MP F1s) and data on LOH (loss of heterozygosity) in
 F2s (asexual offspring of NMP F1s and all offspring of MP F1s), while
 accounting for differences in sample size (*e.g*., different numbers of
 diapause capsules checked for fill rates, different numbers of F2s
 genotyped, different number of variable loci). Sterility rate was
 accounted using fill rate data defined as empty diapause capsule, which we
 indeed found in one MP F1 and one NMP F1 lineage for which males were
 added. Considering the occurrence of mixed reproduction in the main cross,
 demonstrated by a substantial increase in fill rate upon male addition in
 MP and NMP F1 lineages (from 1.67% to 46.5%, Table S4 from) and supported
 by paternity tests (Table S5), it was pertinent to extend our analysis to
 the F2 level. We also jointly analysed LOH rates during asexual
 reproduction. All models can be found in the Mathematica file
 “*Likelihood_models.nb*” that needs the "LOH_DATA.txt" raw data
 file. ### Files and variables #### File: LOH_DATA.txt **Description:** 
 ##### Variables * Pheno: Phenotype of the individual: MP laboratory
 generated F1 male-producing, NMP laboratory generated F1 non-male
 producing, nat: natural obligate parthenogenic lineage, int: intercross
 between MP and NMP * Sample_clone: ID of the maternal lineage *
 Indiv_name: embryo ID * locus_total: total number of informative
 microsatellite loci * locus_homos: number of homozygous microsatellite
 loci * proportion_LOH_obs: proportion of loss of heterozygosity  ####
 File: Likelihood_models.nb **Description:** Likelihood models ##
 Code/software We used Mathematica 13.2.1 (Wolfram Research 2017) ## Access
 information Other publicly accessible locations of the data: *
 Supplemental files of the article from Molinier C., Clément C., Calzan H.,
 Lenormand T., Haag C. R. The arduous path to obligate asexuality in
 *Daphnia*, Proc. R. Soc. B, doi: 10.1098/rspb.2025.2307