Water-siphon test. Dr Henry Knipe â and Dr Marcin Czarniecki â et al. The water siphon test may be performed as part of a barium swallow to assess for gastro-oesophageal reflux in a hiatal hernia. It is performed in the supine RPO position with the patient drinking water continuously. The test is said to be positive if there is visible barium reflux in the oesophagus.
In some instances, offspring can demonstrate a phenotype that is outside the range defined by both parents. In particular, the phenomenon known as overdominance occurs when a heterozygote has a more extreme phenotype than that of either of its parents. Indeed, in a few examples, a trait that shows overdominance sometimes confers a survival advantage in the heterozygote (Parsons & Bodmer, 1961).
Â· just now. Report Abuse. They're passed on through genes. Each chromosome holds a bunch of genes, and during meiosis and mitosis the chromosomes are replicated. Genes of the father and genes of the mother combine, and whatever trait (genotype) is dominant is the trait that is displayed in the offspring (phenotype). have brown eyes that is the expressed phenotype. The genotype is both alleles one from each parent, in my case its heterozygous meaning different alleles, i am Bg. Brown is dominant over blue which in turn is dominant over the recessive green.