DNA RNA strands are created using DNA strands as a template in a process called transcription. Under the genetic code, these RNA strands specify the sequence of amino acids within proteins in a process called translation. Within eukaryotic cells, DNA is organized into long structures called chromosomes. Before typical cell division, these chromosomes are duplicated in the process of DNA replication, providing a complete set of chromosomes for each daughter cell. Eukaryotic organisms (animals, plants, fungi and protists) store most of their DNA inside the cell nucleus and some in organelles, such as mitochondria or chloroplasts. In contrast, prokaryotes (bacteria and
Cell-free fetal DNA available. The test can be performed at nine weeks gestation. Autosomal dominant and recessive single gene disorders which have been diagnosed prenatally by analysing paternally inherited DNA include cystic fibrosis, beta thalassemia, sickle cell anemia, spinal muscular atrophy, and myotonic dystrophy. Prenatal diagnosis of single gene disorders which are due to an autosomal recessive mutation, a maternally inherited autosomal dominant mutation or large sequence mutations that include duplication, expansion or insertion of DNA sequences is more difficult. In cffDNA, fragments of 200 300 bp length involved in single gene disorders are more difficult to detect. For example, the autosomal dominant