The Role of the Sex Chromosomes in the Inheritance of Species Specific Traits of the Shape of the Copulatory Organ in Drosophila

The sex chromosomes of the parental species, D. virilis and D. lummei were tested for the effect on trait dominance in the shape of the copulatory system in the interspecific crosses. The origin of the sex chromosome and the paternal genotype were found to affect the trait dominance in D. lummei × D. virilis progeny and backcross males heterozygous for the autosomes. A correlated variability analysis showed that the two sex chromosomes exert unidirectional effects, shifting dominance towards the conspecific phenotype. The effect of the X chromosome is to a great extent determined by epigenetic factors associated with the paternal genotype.

061. PATERNAL FACTORS INFLUENCING GESTATIONAL OUTCOME IN OFFSPRING

Fetal programming can often be attributed to sub-optimal, but potentially modifiable, maternal factors such as smoking and poor nutrition. Much of the literature in this field points to factors that cause intrauterine growth restriction (IUGR) and the long term consequences for offspring health. It is not greatly appreciated, however, that other complications that may occur with, or independently of, IUGR predispose offspring, and their mothers, to poor health. These include preeclampsia and gestational diabetes. Elevated maternal BMI increases the risk for most pregnancy complications. Our new data show that paternal obesity (BMI>30) and waist circumference >102cm are associated with IUGR. We have also identified polymorphisms in a number of genes that regulate how the placenta differentiates and invades the maternal decidua, and how the mother adapts to pregnancy, that are associated with adverse pregnancy outcomes. Excitingly, many of these are polymorphisms in the paternal genome. One might reasonably expect that these would be found in imprinted genes expressed only from the paternal allele. However, we have also found several non-imprinted genes in which paternal genotype has a significant influence on pregnancy outcome both on maternal and infant disease states, but also on fetal and placental growth parameters. Furthermore, these genes interact with the maternal environment including diet and smoking to profoundly affect maternal and infant health. Consequently we now propose a complicated model of the control of optimal placental and fetal growth and pregnancy outcome that includes important genetic contributions from both parents to placental genotype that regulate conceptus growth and function. Importantly, paternal genotype can influence placental gene expression and the myriad of placental hormones and growth factors secreted into the maternal circulation that modulate maternal adaptation to pregnancy and, in susceptible women, these interact with maternal genotype, BMI and lifestyle to cause poor maternal and infant health.

MICROSATELLITE MARKERS FOR VERIFYING PARENTAGE OF PECANS

Microsatellite or Simple Sequence Repeat (SSR) markers are being developed in ongoing research in the USDA ARS Pecan Breeding Program. These co-dominant markers provide a powerful tool for the verification of parentage. To confirm their utility, SSR profiles were used to confirm the parentage of 19 of the 25 controlled crosses released by the breeding program. Questions were raised concerning the parentage of some crosses thought to be known. When the genotype of the maternal parent is known, the paternal genotype necessary to have produced the progeny can be determined. A SAS program was written to query a database that includes 288 pecan accessions to find appropriate paternal genotypes given a maternal pattern. If neither parent is known, all possible parental combinations can be derived based on the progeny. Putative parents can be qualified on the basis of genotype as well as other evidence, such as nut morphology, dates of origin, locations of origin, and dichogamy. Using these techniques, putative parents are suggested for the historic cultivars `Riverside' and `Western'. Although the probabilities for a particular genotypic pattern can be determined based on allele frequencies within the population, assigning numeric probabilities to other evidence is more challenging. Meticulous records are necessary to establish the linkage between an inventory of an accession and its historic origin, thereby placing putative parents in combination at the proper place and appropriate time. Records of USDA–ARS National Plant Germplasm System, as exemplified by logbooks and vouchers of the McKay Collection of the National Arboretum, provide evidence for confident molecular genetic verification of cultivar identity and parentage, increasing the value of the living accessions in the NPGS.