Dominance and parent-of-origin effects of coding and non-coding alleles at the acylCoA-diacylglycerol-acyltransferase (DGAT1) gene on milk production traits in German Holstein cows

<p>Abstract</p> <p>Background</p> <p>Substantial gene substitution effects on milk production traits have formerly been reported for alleles at the K232A and the promoter VNTR loci in the bovine acylCoA-diacylglycerol-acyltransferase 1 (<it>DGAT1</it>) gene by using data sets including sires with accumulated phenotypic observations of daughters (breeding values, daughter yield deviations). However, these data sets prevented analyses with respect to dominance or parent-of-origin effects, although an increasing number of reports in the literature outlined the relevance of non-additive gene effects on quantitative traits.</p> <p>Results</p> <p>Based on a data set comprising German Holstein cows with direct trait measurements, we first confirmed the previously reported association of <it>DGAT1 </it>promoter VNTR alleles with milk production traits. We detected a dominant mode of effects for the <it>DGAT1 </it>K232A and promoter VNTR alleles. Namely, the contrasts between the effects of heterozygous individuals at the <it>DGAT1 </it>loci differed significantly from the midpoint between the effects for the two homozygous genotypes for several milk production traits, thus indicating the presence of dominance. Furthermore, we identified differences in the magnitude of effects between paternally and maternally inherited <it>DGAT1 </it>promoter VNTR – K232A haplotypes indicating parent-of-origin effects on milk production traits.</p> <p>Conclusion</p> <p>Non-additive effects like those identified at the bovine <it>DGAT1 </it>locus have to be accounted for in more specific QTL detection models as well as in marker assisted selection schemes. The <it>DGAT1 </it>alleles in cattle will be a useful model for further investigations on the biological background of non-additive effects in mammals due to the magnitude and consistency of their effects on milk production traits.</p

A Highly Scalable RFID Authentication Protocol

Abstract. In previous RFID protocols, a hash-chain is used to achieve good privacy. Each tag is associated with a chain of Q hash values. To identify one tag out of a total of N tags, a server searches a table of size NQ. A naive search takes either Θ(NQ) time or Θ(NQ) memory, and therefore it does not scale well. A time-space tradeoff technique can mitigate the scalability problem. However, with the time-memory tradeoff, either time or space is still at least Θ((NQ) 2/3). In this paper, we propose a novel RFID protocol to solve the scalability problem. The server “solves”, instead of “searches”, for a tag ID. The protocol is based on polynomial operations, and its security and privacy is based on the difficulty of reconstructing a polynomial with noisy data. The protocol supports very large values of the product NQ. In our demo implementation where N = 2 32 and Q = 13700, the server takes 0.1 seconds and 10K bytes memory to identify a tag. As a comparison, a hash-chain based protocol enhanced with a time-memory tradeoff will require about 67 seconds and a 1G bytes memory.

Energy-Efficient Implementation of ECDH Key Exchange for Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are playing a vital role in an ever-growing number of applications ranging from environmental surveillance over medical monitoring to home automation. Since WSNs are often deployed in unattended or even hostile environments, they can be subject to various malicious attacks, including the manipulation and capture of nodes. The establishment of a shared secret key between two or more individual nodes is one of the most important security services needed to guarantee the proper functioning of a sensor network. Despite some recent advances in this field, the efficient implementation of cryptographic key establishment for WSNs remains a challenge due to the resource constraints of small sensor nodes such as the MICAz mote. In this paper we present a lightweight implementation of the elliptic curve Diffie-Hellman (ECDH) key exchange for ZigBee-compliant sensor nodes equipped with an ATmega128 processor running the TinyOS operating system. Our implementation uses a 192-bit prime field specified by the NIST as underlying algebraic structure and requires only 5.20·10^6 clock cycles to compute a scalar multiplication if the base point is fixed and known a priori. A scalar multiplication using a random base point takes about 12.33·10^6 cycles. Our results show that a full ECDH key exchange between two MICAz motes consumes an energy of 57.33 mJ (including radio communication), which is significantly better than most previously reported ECDH implementations on comparable platforms