Computers from plants we never made. Speculations

We discuss possible designs and prototypes of computing systems that could be based on morphological development of roots, interaction of roots, and analog electrical computation with plants, and plant-derived electronic components. In morphological plant processors data are represented by initial configuration of roots and configurations of sources of attractants and repellents; results of computation are represented by topology of the roots' network. Computation is implemented by the roots following gradients of attractants and repellents, as well as interacting with each other. Problems solvable by plant roots, in principle, include shortest-path, minimum spanning tree, Voronoi diagram, $\alpha$-shapes, convex subdivision of concave polygons. Electrical properties of plants can be modified by loading the plants with functional nanoparticles or coating parts of plants of conductive polymers. Thus, we are in position to make living variable resistors, capacitors, operational amplifiers, multipliers, potentiometers and fixed-function generators. The electrically modified plants can implement summation, integration with respect to time, inversion, multiplication, exponentiation, logarithm, division. Mathematical and engineering problems to be solved can be represented in plant root networks of resistive or reaction elements. Developments in plant-based computing architectures will trigger emergence of a unique community of biologists, electronic engineering and computer scientists working together to produce living electronic devices which future green computers will be made of.Comment: The chapter will be published in "Inspired by Nature. Computing inspired by physics, chemistry and biology. Essays presented to Julian Miller on the occasion of his 60th birthday", Editors: Susan Stepney and Andrew Adamatzky (Springer, 2017

The effect of pedigree structure on detection of deletions and other null alleles.

Deletions and other null alleles for genetic markers can be detected as a special case of non-Mendelian inheritance, ie when a parent and a child appear to be homozygous for different alleles. The probability to detect a deletion for a fixed overall number of investigated individuals was calculated for biallelic and multiallelic markers with varying allele frequencies. To determine the effect of increasing the number of parents and grandparents, the probability for this event was derived for a parent and one child, a trio, a trio with one grandparent and a trio with two grandparents. The results for biallelic markers show that for a fixed total number of individuals, a sample of trios with two grandparents is always more efficient than the other family types, despite a lower total number of founder chromosomes in the sample. For multiallelic markers the outcome varies. The effect of adding additional children to a nuclear family was also investigated. For nuclear families, the optimal number of children is two or three, depending on the allele frequencies. It is shown that adding children is more efficient than adding grandparents.European Journal of Human Genetics advance online publication, 16 April 2008; doi:10.1038/ejhg.2008.75