Parthenogenesis is development of offspring from an egg without fertilization. It can be a regular reproductive mode or occur facultatively in a lineage that also reproduces sexually. The term describes the absence of fertilization; it does not by itself specify chromosome number or guarantee offspring genetically identical to the mother.[ref]
Parthenogenesis in Komodo dragons by Phillip C. Watts and others. Opening definition and observations of facultative reproduction
A simple genetic example shows the distinction from cloning. Suppose a diploid mother has alleles and at one locus. If a haploid egg carrying restores diploidy by copying its own chromosome set, the offspring is , not the mother's . An egg carrying would give . This illustrates one possible mechanism, not every route of parthenogenesis.
The 2006 Komodo-dragon study tested offspring from females isolated from males using microsatellite markers. The offspring carried maternal alleles but were homozygous at the tested loci and were not identical clones. Comparisons with potential fathers and the distribution of alleles across the clutch supported parthenogenesis rather than ordinary fertilization. One female later produced offspring sexually, showing that the observed reproductive mode was facultative.[ref]
Parthenogenesis in Komodo dragons by Phillip C. Watts and others. Main text and supplementary genotype table: parental exclusion, homozygosity, nonidentical offspring and later sexual reproduction
An isolated female producing eggs is therefore suggestive but not sufficient evidence: prior mating and sperm storage can be alternative explanations in suitable species. Developmental observations and genetic parentage evidence answer different parts of the question.
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