Do the x and y chromosomes recombine at all?If so does that mean a
girl inherits some genes from her fathers y chromosome?

Hello.

Most of the Y chromosome does NOT recombine.

"The Y chromosome has become a genetic junkyard because it does not
recombine -- recombination is the swapping of DNA that occurs between
paired chromosomes when eggs and sperm are made.
  In fact, 95% of the Y chromosome never swaps DNA with the X. This
includes the region that contains the gene specifying maleness.
Researchers believe that this is how sex chromosomes acquired their
roles, with chromosomal rearrangements causing the X and Y to become
isolated from each other."

source: "The Y chromosome: goldmine and junkyard"
http://www.nature.com/nsu/010215/010215-5.html


"During the formation of sperm, as the other chromosomes shuffle their
genes, only a small section of the Y chromosome exchanges bits of
material with its partner. Most of it remains aloof, providing a
clean, unmuddled pedigree passed down from father to son--a male
counterpart to mitochondrial DNA."

source: "After You, Eve".(Y chromosome research)"
http://www.findarticles.com/cf_dls/m1134/2_110/71317735/p3/article.jhtml?term=

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As the above quotations imply, though, a tiny part of the Y chromosome
DOES recombine.

"The recent publication in Nature of the sequence of the male-specific
portion of the human Y chromosome (MSY; ref. 2) presents a different
picture, however, of an extraordinary part of the genome shaped by a
strange history of haploidy.
  The MSY constitutes about 90% of the euchromatic length of the human
Y chromosome, with the remainder residing in pseudoautosomal regions
that recombine with counterparts on the tips of the X chromosome. "
source: Nature Genetics:A singular chromosome
http://www.nature.com/cgi-taf/DynaPage.taf?file=/ng/journal/v34/n3/full/ng0703-246.html

"The X and Y have homologous regions (i.e., with matching gene loci)
which pair up during meiosis (synapsis) and undergo limited crossing
over. These regions of homology are called PSEUDOAUTOSOMAL regions.
Most of the X and Y are not homologous, however, and undergo NO CROSSING OVER."
source: Miami.edu: SEX CHROMOSOMES
http://www.bio.miami.edu/dana/104/104F02_8.html


"The Pseudoautosomal Regions
The pseudoautosomal regions get their name because any genes located
within them (so far only 9 have been found) are inherited just like
any autosomal genes. Males have two copies of these genes: one in the
pseudoautosomal region of their Y, the other in the corresponding
portion of their X chromosome. So males can inherit an allele
originally present on the X chromosome of their father and females can
inherit an allele originally present on the Y chromosome of their
father."
source:
Kimball's Biology Pages: Sex Chromosomes
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexChromosomes.html#The_Pseudoautosomal_Regions


Thus, as the last quotation plainly states, a girl can inherit some
genes from a her father's Y-chromosome (but only a few).

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search strategy:
"Y chromosome never"
"pseudoautosomal regions", y chromosome

I hope this helps.

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Request for Answer Clarification by arkin-ga on 08 Jan 2004 23:04 PST

Thanks for your answer,it was very well done.I was just
wondering,though, does that mean a female only could inherit a few
genes or they always inherit a few genes?Thanks again.

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Clarification of Answer by juggler-ga on 09 Jan 2004 01:47 PST

First of all, just so that we're clear on the big picture...  Girls
inherit half of their genes from their fathers. A girl has 46
chromosomes containing tens of thousands of genes. Half of the genetic
material on those chromosomes is from her father.

Here, we're just talking about whether ONE of a girl's X-chromosomes
(out of 46 chromosomes) has genetic material from her father's
Y-chromosome.  As indicated, the answer is "yes."

Two tiny regions of the Y-chromosome recombine with their counterparts
on the paired X chromosome.

These regions are called Pseudoautosomal Regions (PAR1 & PAR2).

"The Pseudoautosomal regions (PAR): PAR1 is located at the terminal
region of the short arm (Yp), and the PAR2 at the tip of the long arm
(Yq). PAR1 and PAR2 cover approximately 2600 and 320 kb of DNA,
respectively. The pseudoautosomal regions, and in particular PAR1, are
where the Y chromosome pairs and exchanges genetic material with the
pseudoautosomal region of the X chromosome during male meiosis.
Consequently, genes located within the PAR are inherited in the same
manner as autosomal genes."
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=79676

"The Pseudoautosomal regions (PAR): PAR1 is located at the terminal
region of the short arm (Yp), and the PAR2 at the tip of the long arm
(Yq). PAR1 and PAR2 cover approximately 2600 and 320 kb of DNA,
respectively. The pseudoautosomal regions, and in particular PAR1, are
where the Y chromosome pairs and exchanges genetic material with the
pseudoautosomal region of the X chromosome during male meiosis.
Consequently, genes located within the PAR are inherited in the same
manner as autosomal genes. "
http://www.pubmedcentral.gov/picrender.fcgi?action=stream&blobtype=pdf&artid=79676


These Pseudoautosomal Regions are characterized as areas of "extremely
high" recombination.

"...within the 2 X-Y homologous pseudoautosomal regions (PAR1 and
PAR2), recombination frequencies are extremely high. Indeed, PAR1 on
Xp/Yp exhibits one of the highest recombination rates in male meiosis
in the human genome."
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=OMIM&dopt=Detailed&tmpl=dispomimTemplate&list_uids=300162

Considering the high recombination rate of PAR1, a female always
inherits SOME genetic material from her father's Y chromosome.

I hope this helps.

Thanks for your answer,it was really helpful.

I know this is terribly geeky of me, but this is the most interesting
thing I read today!   Neat Question and a nicely done Answer!

regards, mathtalk-ga