This prevents mutant Y chromosome genes from being eliminated from male genetic lines except by inactivation or deletion. Medical Genetics. In women, a recessive allele on one X chromosome is often masked in their phenotype by a dominant normal allele on the other.
Login processing An example of this can be seen in hemophilia. Human disorders attributable to multifactorial inheritance alcoholism Alzheimer disease cancer coronary heart disease diabetes epilepsy hypertension obesity schizophrenia. If you need immediate assistance, please email us at support jove.
Duchenne muscular dystrophy.
All rights reserved. Only one of the Y chromosome genes, the SRY gene, is responsible for male anatomical traits. Philadelphia, PA: Elsevier Saunders; chap However, the Y chromosome doesn't contain most of the genes of the X chromosome. Carriers can pass abnormal genes to their children.
The authors suggest that this could happen in up to 1 in 20, genetically male embryos XY. This prevents mutant Y chromosome genes from being eliminated from male genetic lines except by inactivation or deletion. Her son Leopold had the disease and died at age 30, while her daughters were only carriers.
Because the Y chromosome only experiences recombination with the X chromosome at the ends as a result of crossing-over , the Y chromosome essentially is reproduced via cloning from one generation to the next. And so some of the more familiar sex-linked traits are hemophilia, red-green color blindness, congenital night blindness, some high blood pressure genes, Duchenne muscular dystrophy, and also Fragile X syndrome.
When any of the 9 genes involved in sperm production are missing or defective the result is usually very low sperm counts and subsequent infertility.