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A ZZ/ZW Sex Chromosome System in Cephalochordate Amphioxus
- Source :
- Genetics
- Publication Year :
- 2020
- Publisher :
- Oxford University Press (OUP), 2020.
-
Abstract
- Sex determination is remarkably variable among animals with examples of environmental sex determination, male heterogametic (XX/XY) and female heterogametic (ZZ/ZW) chromosomal sex determination, and other genetic mechanisms. The cephalochordate amphioxus occupies a key phylogenetic position as a basal chordate and outgroup to vertebrates, but its sex determination mechanism is unknown. During the course of generating Nodal mutants with transcription activator-like effector nucleases (TALENs) in amphioxus Branchiostoma floridae, serendipitously, we generated three mutant strains that reveal the sex determination mechanism of this animal. In one mutant strain, all heterozygous mutant offspring over three generations were female and all wild-type descendants were male. This pattern suggests the Nodal allele targeted is on a female-specific W chromosome. A second mutant showed the same W-linked inheritance pattern, with a female heterozygote passing the mutation only to daughters. In a third mutant strain, both male and female offspring could be heterozygous, but a female heterozygote passed the mutation only to sons. This pattern is consistent with the targeted allele being on a Z chromosome. We found an indel polymorphism linked to a Nodal allele present in most females, but no males in our cultured population. Together, these results indicate that Nodal is sex chromosome-linked in B. floridae, and that B. floridae has a ZZ/ZW sex chromosome system.
- Subjects :
- Male
Genetics
education.field_of_study
Z chromosome
Sex Chromosomes
Population
Environmental sex determination
Chromosome
Investigations
Sex Determination Processes
Biology
biology.organism_classification
W chromosome
Branchiostoma floridae
Animals
Female
Allele
education
Alleles
Phylogeny
Heterogametic sex
Lancelets
Subjects
Details
- ISSN :
- 19432631
- Volume :
- 214
- Database :
- OpenAIRE
- Journal :
- Genetics
- Accession number :
- edsair.doi.dedup.....3d1e490312c359edf396b4aea26df2d4