No human is a clone of their parents but the same cannot be said for other living things. While your DNA is a combination of half your mother and half your father, other species do things differently. The advantage of clonal reproduction is that it produces an individual exactly like an existing onewhich would be very useful for farmers who could replicate the best of their animals or crops without the lottery of sexual reproduction. Clonal reproduction of crop species took a step closer to being realised with new research published in PLoS Biology this week.
The type of cell division that creates eggs and sperm is called meiosis, and it differs from 'normal' cell division (mitosis) because instead of producing two genetically identical daughter cells, it produces four cells each containing only half of the parental amount of DNA. Meiosis occurs in all species that reproduce sexually, from microorganisms such as yeast to plants, animals and human beings. This new paper blurs the line between the two different types of cell division by showing a plant where three specific mutations are experimentally combined. These divisions are normally meiotic which make pollen and egg cells and are replaced by mitotic divisions. The work, by a team of researchers in France and Austria, is potentially very important commercially, because it makes the creation of stable new mutant cropssuch as plants of a different colour, or with a different yield, etc.much simpler. It is now much closer to being po ssible to reproduce a plant that produces perfect potatoes, maize or rice, without the lottery of reassortment that each meiotic division and ensuing fertilization introduces.
The first steps of both meiosis and mitosis are the replication of the dividing cell's DNA. Once replication has occurred, the chromosomes condense into tightly bound structures, and in mitosis these form an X shape in which each half of the X is a chromatid, comprising one com
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