The lengths at birth (Lb) of mother cells and daughter cells are plotted against each other to see how they correlate.

A grey dot in point (X,Y) of the plane symbolizes that several cells had a length X for the mother and a length Y for the daughter, with the intensity of the gray color indicating how many cells fit there (a bigger number of cells indicated by a more intense shade of gray, upt to 63 units for the most-gray shade, as indicated by the right vertical bar).

Suppose a simpler scenario in which the length of a daughter were always exactly the same as the length of its mother. Then we would have X=Y for every gray dot and we would see the dots exactly fitting the y=x line, in an ordered array, but we could have more dots, and more intense, in some parts than in others, since for example the 2.5um length could be more usual than the 4um one, because of biological reasons.

In the real case, since a lot of combinations of mother and daughter lengths are possible and we don't have an exact process but an statistical one, we see a cluster of gray dots, expressing a multiplicity of real-life possibilities. But the distribution is not totally random, the gray dots tend to accumulate and be more intense on some spot around the mean.

This cluster of dots is useful to see, but not illuminating. For that cause, a sort of summary is included, in the form of the red dots, which are more or less like a histogram (the information of the gray points is collapsed into several specified ranges of values). Is this set of red dots which we can more readily interpret.

We can see, looking at the y=x line, that when the length of the mother is small (i.e., when the X value is near the origin of coordinates) the length Y of the daughter tends to be bigger than that of its mother, since the red dots are above the y=x line (so the gray dots, accounted for their intensity, have the same property). Similarly, when the length of the mother is large, the length of the daughter tends to be smaller, since the red dots are below the y=x line in the right part of the graph. Lastly, around the mean (which is near 2.5um for the mothers and less near to 2.5um for the daughters, as marked by the dotted vertical and horizontal lines), the length of the daughters is quite similar, but slightly smaller, than that of their mothers.

Hey Jose,

Thanks a million. I have never read such pretty simple illustration that was so easy to be understood.

Appreciating your time for writing such long helpful illustration.

Best,