– **History**:
– German zoologists Oscar and Richard Hertwig discovered animal zygote formation in the late 19th century.
– **In multicellular organisms**:
– The zygote is the earliest developmental stage.
– Zygote formation involves the fusion of egg and sperm cells.
– Epigenetic reprogramming is crucial for zygote totipotency.
– DNA demethylation in the paternal genome is essential for epigenetic reprogramming.
– Demethylation processes involve base excision repair and other mechanisms.
– **Humans**:
– Human fertilization results in the formation of a diploid zygote.
– The zygote undergoes divisions and forms blastomeres.
– The conceptus transitions into a blastocyst before implantation.
– Genetic editing of human zygotes has been explored for disease treatment.
– **Fungi**:
– In fungi, the zygote may undergo meiosis or mitosis based on species’ life cycles.
– **Plants**:
– Zygotes in plants may be polyploid under specific fertilization conditions.
– The zygote forms within an archegonium in land plants.
– Seedless plant zygotes develop inside flask-shaped archegonia.
– Zygote growth and division occur within the archegonium.
– **In single-celled organisms**:
– Zygotes can asexually divide through mitosis.
– Chlamydomonas zygotes may contain chloroplast DNA from both parents.
– Biparental zygotes in Chlamydomonas allow mapping of chloroplast genes.
A zygote (/ˈzaɪˌɡoʊt/; from Ancient Greek ζυγωτός (zygōtós) 'joined, yoked', from ζυγοῦν (zygoun) 'to join, to yoke') is a eukaryotic cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individual organism. The sexual fusion of haploid cells is called karyogamy, the result of which is the formation of a diploid cell called the zygote or zygospore.
| Zygote | |
|---|---|
 Zygote formation: egg cell after fertilization with a sperm. The male and female pronuclei are converging, but the genetic material is not yet united. | |
| Details | |
| Days | 0 |
| Precursor | Gametes |
| Gives rise to | Blastomeres |
| Identifiers | |
| MeSH | D015053 |
| TE | E2.0.1.2.0.0.9 |
| FMA | 72395 |
| Anatomical terminology | |