A man with attached ear lobes marries a woman who is heterozygous for free ear lobes. What types of offspring?

Question

is produced, indicate the proportion of each type.
2. What explanations might be proposed for the relationship between increaing naternal age and the increasing frequency of Down's syndrome?

Answer 1

let's say that
free ear lobes= F
attached ear lobes= f
parents gametes in a punnet square:
l F l f
--l----l-----
F l FF l Ff
-------l----
f l Ff l ff
as a result the phenotypic ratio is 1(attached ear lobe): 3 (free ear lobe)

if both parents have attached ear lobes, they have to be homozygous
(for the recessive trait to be shown phenotypically in this case it
has to come in a double doze) thereby 100% chance of getting child
with attached ear lobe.

Answer 2

use the punnet square... A=attached a=unattached
A A
A= AA AA

a= Aa Aa

100% attached

Down Syndrome has to do with an extra chromosome developing. As a woman's age increases the more likely the problems with cell division.

Answer 3

I'll skip question one, but one explanation that has been posed as to why women of advanced maternal age have a higher "risk" of having a child with Down syndrome is that younger women who get a prenatal diagnosis of DS (sadly) may be more inclined to terminate their pregnancy, thus there are more live births of babies with DS to older women. Having said that, I have a son with DS and am active in the DS community and most of the moms I know are quite young. I think it is a dated theory that needs revisiting.

Answer 4

Roughly 50% of the children will be lazy bums who don't do their own homework, 25% morons, and 25% normal.

Answer 5

ooh i learnt approximately that during biology!! its an inherited gene.. i looked at mine.. and that i do only no longer understand.. it ought to be one.. or the different.. i only dont understand.. i think of it ought to be loose falling =P

Answer 6

crazy!