A large scale hearing loss screen reveals an extensive unexplored genetic landscape for auditory dysfunction

The developmental and physiological complexity of the auditory system is likely reflected in the underlying set of genes involved in auditory function. In humans, over 150 non-syndromic loci have been identified, and there are more than 400 human genetic syndromes with a hearing loss component. Over 100 non-syndromic hearing loss genes have been identified in mouse and human, but we remain ignorant of the full extent of the genetic landscape involved in auditory dysfunction. As part of the International Mouse Phenotyping Consortium, we undertook a hearing loss screen in a cohort of 3006 mouse knockout strains. In total, we identify 67 candidate hearing loss genes. We detect known hearing loss genes, but the vast majority, 52, of the candidate genes were novel. Our analysis reveals a large and unexplored genetic landscape involved with auditory function

RNAi knockdown of the flightless-I transcript in Drosophila melanogaster

Thesis (M.S.)--University of Hawaii at Manoa, 2007.Includes bibliographical references (leaves 63-69).69 leaves, bound ill. (some col.) 29 c

Universal Southern blot protocol with cold or radioactive probes for the validation of alleles obtained by homologous recombination

International audienc

Long-read sequencing for fast and robust identification of correct genome-edited alleles: PCR-based and Cas9 capture methods.

BackgroundRecent developments in CRISPR/Cas9 genome-editing tools have facilitated the introduction of precise alleles, including genetic intervals spanning several kilobases, directly into the embryo. However, the introduction of donor templates, via homology directed repair, can be erroneous or incomplete and these techniques often produce mosaic founder animals. Thus, newly generated alleles must be verified at the sequence level across the targeted locus. Screening for the presence of the desired mutant allele using traditional sequencing methods can be challenging due to the size of the interval to be sequenced, together with the mosaic nature of founders.Methodology/principal findingsIn order to help disentangle the genetic complexity of these animals, we tested the application of Oxford Nanopore Technologies long-read sequencing at the targeted locus and found that the achievable depth of sequencing is sufficient to offset the sequencing error rate associated with the technology used to validate targeted regions of interest. We have assembled an analysis workflow that facilitates interrogating the entire length of a targeted segment in a single read, to confirm that the intended mutant sequence is present in both heterozygous animals and mosaic founders. We used this workflow to compare the output of PCR-based and Cas9 capture-based targeted sequencing for validation of edited alleles.ConclusionTargeted long-read sequencing supports in-depth characterisation of all experimental models that aim to produce knock-in or conditional alleles, including those that contain a mix of genome-edited alleles. PCR- or Cas9 capture-based modalities bring different advantages to the analysis

Application of long single-stranded DNA donors in genome editing: generation and validation of mouse mutants

Abstract Background Recent advances in clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) genome editing have led to the use of long single-stranded DNA (lssDNA) molecules for generating conditional mutations. However, there is still limited available data on the efficiency and reliability of this method. Results We generated conditional mouse alleles using lssDNA donor templates and performed extensive characterization of the resulting mutations. We observed that the use of lssDNA molecules as donors efficiently yielded founders bearing the conditional allele, with seven out of nine projects giving rise to modified alleles. However, rearranged alleles including nucleotide changes, indels, local rearrangements and additional integrations were also frequently generated by this method. Specifically, we found that alleles containing unexpected point mutations were found in three of the nine projects analyzed. Alleles originating from illegitimate repairs or partial integration of the donor were detected in eight projects. Furthermore, additional integrations of donor molecules were identified in four out of the seven projects analyzed by copy counting. This highlighted the requirement for a thorough allele validation by polymerase chain reaction, sequencing and copy counting of the mice generated through this method. We also demonstrated the feasibility of using lssDNA donors to generate thus far problematic point mutations distant from active CRISPR cutting sites by targeting two distinct genes (Gckr and Rims1). We propose a strategy to perform extensive quality control and validation of both types of mouse models generated using lssDNA donors. Conclusion lssDNA donors reproducibly generate conditional alleles and can be used to introduce point mutations away from CRISPR/Cas9 cutting sites in mice. However, our work demonstrates that thorough quality control of new models is essential prior to reliably experimenting with mice generated by this method. These advances in genome editing techniques shift the challenge of mutagenesis from generation to the validation of new mutant models

Additional file 18: of Application of long single-stranded DNA donors in genome editing: generation and validation of mouse mutants

Figure S16. Generation of a point mutation in Rims1 with ssODN donors. (a) The table details the F0 animals obtained for generation of Rims1 mutant with ssODN donors. The ID and outcome of sequencing the region of interest, as well as the conclusion for each individual are shown. (b) PCR amplification of region of interest with Rims1-F1 and Rims1-R1 primers (241 bp) from biopsies taken from the F0 animals. Sequences of Rims1-ODN-151 mosaic and of sub-cloned amplicons are shown in Additional file 3: Figure S2u and v, demonstrating the presence of the desired mutation in this animal that was therefore mated. (c) PCR amplification of region of interest with Rims1-F1 and Rims1-R1 primers (241 bp) from biopsies taken from Rims1-ODN-151’s offspring. Animal IDs are shown. + is positive control amplified from an unrelated WT animal. L1 = 1 kb DNA molecular weight (thick bands are 3 kb); L2 = 100 bp DNA molecular weight ladder (thick bands are 1000 and 500 bp). (d) The table details the first litter obtained by mating Rims1-ODN-151 with a WT mouse. The ID, outcome of sequencing the region of interest and copy counting of the region of interest as well as the conclusion for each individual are shown. Sequencing of Rims1-ODN-151.1g is shown in Additional file 3: Figure S2w and illustrates the failure of transmission of the desired allele. (PNG 893 kb

Additional file 20: of Application of long single-stranded DNA donors in genome editing: generation and validation of mouse mutants

The file contains the raw sequencing data obtained from the founders generated for the Rims1R655H point mutation. (ZIP 21747 kb

Percentage of WT sequence recall with Fast basecalled data across a range of read depths.

This table summarises the percentage of WT sequence recall with Fast basecalled data across a range of depth of sequencing values with consensus thresholds ranging from 50% to 90%. (PDF)</p

Analysis of the G₁ generation containing animals interrogated by ONT sequencing for the <i>Inpp5k</i>-flox project.

The figure shows the PCR amplification of the genomic region of interest with (A) Inpp5k-F1 and Inpp5k-R1 primers (WT yields 1701 bp amplicon, floxed allele yields 1705 bp amplicon) and (B) LoxPF and LoxPR primers (floxed allele yields 1194 bp amplicon) from biopsies taken from the G1 animals derived from crossing founder animals Inpp5k-7 and Inpp5k-8 to WT. (C) The table details the G1 animals obtained from the two lines. The ID and outcome of PCR analysis of the region of interest, as well as the conclusion for each individual are shown. (D) The panels show the sequencing of PCR amplicon obtained from animal Inpp5k-7.1b with Inpp5k-F1 and LoxPR, and with LoxPF and Inpp5k-R1 respectively. (E) shows the sequencing of PCR amplicon obtained from animal Inpp5k-8.3d. Deviations from the intended mutant sequence are highlighted in blue. Animal(s) interrogated by ONT sequence analysis are highlighted in green. + is positive control amplified from an unrelated (A) WT, (B) floxed animal. L1 = 1 kb DNA molecular weight ladder (thick band is 3 kb). (TIF)</p

Percentage of WT sequence recall with HAC basecalled data across a range of Filtlong thresholds.

This table summarises the percentage of WT sequence recall across a range of Filtlong threshold values with consensus thresholds ranging from 50% to 100%. (PDF)</p