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Heterogonesis
Heterogonesis describes the segregation of parental genomes into distinct cell lineages in the dividing zygote. Fertilisation occurs when an ovum fuses with a sperm, forming a zygote. Normally, the genomes of the two parents assort into two diploid bi-parental daughter cells. In a heterogoneic cell division, the genome of only one parent assorts into a single daughter cell following the formation of a tripolar (rather than the normal bipolar) spindle apparatus. Heterogonesis allows for chromosomal segregation to occur in a dispermic fertilisation which may subsequently result in chimerism or sesquizygosis. The term heterogonesis was coined in 2016 by Destouni and Vermeesch who observed the phenomenon in bovine Bovines (subfamily Bovinae) comprise a diverse group of 10 genera of medium to large-sized ungulates, including cattle, bison, African buffalo, water buffalos, and the four-horned and spiral-horned antelopes. The evolutionary relationship betwe ... zygotes. The word is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sesquizygotic Twin
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or ''dizygotic'' ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In rare cases twins can have the same mother and different fathers (heteropaternal superfecundation). In contrast, a fetus that develops alone in the womb (the much more common case, in humans) is called a ''singleton'', and the general term for one offspring of a multiple birth is a ''multiple''. Unrelated look-alikes whose resemblance parallels that of twins are referred to as doppelgängers. Statistics The human twin birth rate in the United States rose 76% fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
