Author Topic: HOW DEFECTS ARE INHERITED  (Read 24236 times)

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Offline CilmiSabca

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HOW DEFECTS ARE INHERITED
« on: September 07, 2011, 02:57:31 PM »
   All the good & beautiful things a baby is are a result of the genes he or she inherited from both parents, as well as the environment in the uterus during the nine months of gestation. But the not-so-good things a baby is born with--a birth defect, for instance are also a result of genes and/or environment. Usually the genes a parent passes on to a child are inherited from his or her own parents, but occasionally a gene changes (because of an environmental insult or some unknown factor) and this mutation is passed on.

   There are several kinds of inherited disorders:
* Polygenic disorders (such as clubfoot & cleft lip) are believed to be inherited through the interaction of a number of different genes in much the same way that eye color & height are determined.
* Multifactorial disorders (such as some forms of diabetes) involve the interaction of different genes and environmental conditions (either prior to birth or after it).
* Single-gene disorders can be passed on through either recessive or dominant inheritance. In recessive inheritance,  two genes (one from each parent) must be passed on for the offspring to be affected. In dominant inheritance, just one gene is needed, and it is passed on by a parent who also has the disorder (by virtue of having the gene). Single-gene disorders can also be sex linked (hemophilia, for example). These disorders, carried in genes on the sex-determining chromosomes (females have two X-chromosomes and males one X and one Y), are most often passed from carrier mother to affected son. The male child, having only one X chromosome, has no opposite gene to counteract the one carrying the defect and is affected with the disorder. A female child receiving the gene on an X chromosome from her mother has also received a normal X chromosome from her father, which makes her a carrier but leaves her unaffected by the disorder.
Salam.ental insult or some unknown factor) and this mutation is passed on.

   There are several kinds of inherited disorders:
* Polygenic disorders (such as clubfoot & cleft lip) are believed to be inherited through the interaction of a number of different genes in much the same way that eye color & height are determined.
* Multifactorial disorders (such as some forms of diabetes) involve the interaction of different genes and environmental conditions (either prior to birth or after it).
* Single-gene disorders can be passed on through either recessive or dominant inheritance. In recessive inheritance,  two genes (one from each parent) must be passed on for the offspring to be affected. In dominant inheritance, just one gene is needed, and it is passed on by a parent who also has the disorder (by virtue of having the gene). Single-gene disorders can also be sex linked (hemophilia, for example). These disorders, carried in genes on the sex-determining chromosomes (females have two X-chromosomes and males one X and one Y), are most often passed from carrier mother to affected son. The male child, having only one X chromosome, has no opposite gene to counteract the one carrying the defect and is affected with the disorder. A female child receiving the gene on an X chromosome from her mother has also received a normal X chromosome from her father, which makes her a carrier but leaves her unaffected by the disorder.
Salam.


Talo SAARO Allaah


Offline Akhaa Binu Jowhari

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Re: HOW DEFECTS ARE INHERITED
« Reply #1 on: October 22, 2017, 09:06:09 PM »
Thanks alot, Mr Cilmi
received it, and got much more benefits the Question on Hemophilia........My Allh Grany you the best!
Allow Dhakhaatiirteenna Noo Dhowr Meel Walba Oo Ay Joogaan.

Aamiin Aamiin.