3.1245 skipping generations (76)

Willard McCarty (MCCARTY@vm.epas.utoronto.ca)
Fri, 30 Mar 90 23:31:01 EST

Humanist Discussion Group, Vol. 3, No. 1245. Friday, 30 Mar 1990.


(1) Date: Fri, 30 Mar 90 11:35:30 EST (33 lines)
From: koontz@alpha.bldr.nist.gov (John E. Koontz)
Subject: Re: 3.1234 queries (95) - Skipping Generations

(2) Date: Fri, 30 Mar 90 09:55:01 EST (24 lines)
From: ZAK@NIHCU
Subject: Skipping Generations

(1) --------------------------------------------------------------------
Date: Fri, 30 Mar 90 11:35:30 EST
From: koontz@alpha.bldr.nist.gov (John E. Koontz)
Subject: Re: 3.1234 queries (95) - Skipping Generations

RE: Subject: Skipping generations

> I am trying to gather information about myths, stories, etc.
>that involve skipping generations. For example, a curse, a blessing,
>an attribute that is passed on but skips a generation. While I'm
>asking, can anyone tell me anything about such a phenomenon in
>genetics (scientific or folk)? Isn't male baldness such an instance?
>Any leads would be appreciated.
> Herb Donow

"Male pattern baldness," the usual form of baldness is supposed to be
inherited from one's mother. If your maternal grandfather was bald, and you
are a male, you will probably be bald, too. I have this essentially as folk
knowledge, but believe it has a scientific basis. Hey - it works for me!
This does skip a generation, but only because the trait is exhibited only in
males.

I have also been told by my father (not a geneticist) that identical twins
tend to occur in alternate generations, again being inherited in the female
line.

As I understand the genetics of sickle cell anemia, it would also be
reflected in a somewhat similar way in an area with endemic malaria. Those
who have the trait as a recessive would live, those who lacked it would die
young of malaria, those who has it as a dominant trait would die young of
anemia. Like baldness trait this would be reflected in the exhibitors rather
than the carriers.


(2) --------------------------------------------------------------31----
Date: Fri, 30 Mar 90 09:55:01 EST
From: ZAK@NIHCU
Subject: Skipping Generations

From: GA0708@SIUCVMB
> I am trying to gather information about myths, stories, etc.
> that involve skipping generations. For example, a curse, a blessing,
> an attribute that is passed on but skips a generation. While I'm
> asking, can anyone tell me anything about such a phenomenon in
> genetics (scientific or folk)? Isn't male baldness such an instance?
> Any leads would be appreciated.
> Herb Donow

Baldness doesn't skip a generation; it's an X-linked trait
(carried on the chromosome of the 23rd pair that you inherit from
your mother). Your mother isn't bald because the other member of
the 23rd pair has a normal allele. You, her son, are bald
because your other 23rd chromosome is less massive, has less
genetic information, and is missing the normal gene that offsets
the gene for baldness on the other chromosome. You, however, can
pass the trait on to a daughter (who will not show the phenotype,
but will be able to pass it along to her sons). The trait doesn't
actually skip generations; the phenotypic expression does.