Genes are segments of deoxyribonucleic acid DNA that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are made of a very long strand of DNA and contain many genes hundreds to thousands. Except for certain cells for example, sperm and egg cellsevery human cell contains 23 pairs of chromosomes.
Every new individual is the result of an egg cell merging with a sperm cell. We also know see DNA transfer that our sex cells are formed by reduction division, which reduces the number of chromosomes by half. As a result these are the only cells in the body that have just 23 chromosomes rather than 23 pairs.
Autosomal Recessive. Meconium ileus caused by thick, mucoid meconiumrespiratory bronchiectasis, Pseudomonas pneumonia, pancreatic insufficiency, hypertonic high Cl - concentration sweat. Normocytic anemia with neutropenia.
Switch to new thesaurus. Turner's syndrome - a chromosomal disorder in females who have only one X chromosome; marked by dwarfism and heart abnormalities and underdeveloped sex organs. Mentioned in? References in periodicals archive?
Sex chromosomes are found within our reproductive cells and determine the sex of an individual. Traits are passed on from one generation to the next by our genes. One allele for a trait is inherited from each parent.
Some genetic conditions are caused by mutations in a single gene. These conditions are usually inherited in one of several patterns, depending on the gene involved:. Many health conditions are caused by the combined effects of multiple genes described as polygenic or by interactions between genes and the environment.
A gene present on one of the sex chromosomes X or Y in mammals is a sex-linked trait because its expression depends on the sex of the individual. In humans, as well as in many other animals and some plants, the sex of the individual is determined by sex chromosomes. However, there are other sex determination systems in nature.
Genes come in pairs. Chromosomes are the structures inside cells that carry genes. Chromosomes also come in pairs. Most cells have 23 pairs of chromosomes for a total of 46 chromosomes.
Sex Linked Genes. A particularly important category of genetic linkage has to do with the X and Y sex chromosomes. These not only carry the genes that determine male and female traits but also those for some other characteristics as well.