• The Jax Myo10^m1J allele (MGI:5578506) that was recently reported (MGI - direct submission, J:214794) has an 8-bp deletion in exon 25 that also deletes full-length and the three headless forms of Myo10, but it cannot be used for B-gal labeling and lacks conditional potential.
• The Myo10^{tm2(KOMP)Wtsi} mouse that is being characterized by the KOMP includes a splice acceptor upstream of exon 19 and a 9.5 kb deletion that begins in exon 19 and extends into the first part of intron 19-20. The tm2 allele is thus expected to disrupt full-length Myo10 and the first headless Myo10 transcript, but not the other two headless transcripts. The tm2 allele should be usable for B-gal labeling to visualize the expression of full-length Myo10, but should not report the expression of the headless transcripts. Due to the large 9.5-kb deletion in exon 19 and intron 19-20, the tm2 allele lacks conditional potential.
  
• The Myo10^tm1a allele is unique because it has conditional potential that targets all forms of Myo10 (full-length and the three headless transcripts).
  

Approximately half of Myo10^tm1a homozygotes exhibit the lethal neural tube defect of exencephaly. The tm1a homozygotes that are not affected by exencephaly exhibit 100% incidence of a white belly-spot and 100% incidence of persistent hyaloid vasculature. Numerous other eye defects are observed at lower frequencies including anophthalmia, microphthalmia, coloboma, and defects in lens formation. Approximately half of tm1a homozygotes exhibit syndactyly. Based on KOMP data, tm2 homozygotes also have white belly spots and a high incidence of persistent hyaloid vasculature. Based on the characterization reported in our manuscript on Myo10 null mice, the tm1a and m1j alleles exhibit a similar core phenotype, but the tm1a allele has conditional potential, making it very useful given the high level of lethality in Myo10 nulls and the large number of defects in the nulls.

Homozygous: Born at less than half of the expected Mendelian ratio, which attributed largely to the high frequency (~50%) of exencephaly in the homozygotes. Homozygotes that are not exencephalic are able to develop into adult mice and breed. Homozygotes average ~20% lighter in weight than wild-type and 100% of homozygotes had a white belly spot. 100% of homozygotes whose eyes were dissected exhibited persistent fetal vasculature. Approximately 50% of Myo10tm1a homozygotes exhibited webbed digits.

Hetero/Hemizygous: Heterozygotes appear normal and are not obviously different from wild-type.

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Heimsath EG Jr, Yim YI, Mustapha M, Hammer JA, Cheney RE. Myosin-X knockout issemi-lethal and demonstrates that myosin-X functions in neural tube closure,pigmentation, hyaloid vasculature regression, and filopodia formation. Sci Rep.2017 Dec 11;7(1):17354. doi: 10.1038/s41598-017-17638-x. (Medline PMID: 29229982)