Question in English:
A female carries a recessive lethal gene (l) on one of her X chromosomes, and a normal dominant allele (L) on the other. What is the sex ratio to be expected in this woman's dependency if she marries a normal man?
Answer:
2/3 females
1/3 males
Explanation:
Females have two X chromosomes (XX) and males have an X and a Y chromosome (XY).
The genotype of the female is XLXl. The genotype of the male is XLY, since he is normal.
The possible genotypes are:
<u> XL Xl</u>
<u>XL</u> <em>XLXL XLXl</em>
<u>Y</u> <em>XLY </em><em>XlY</em>
<em />
All female offspring will be normal as they will always have one normal copy of the X chromosome from their father.
50% of the male offspring will be normal, but 50% will inherit the lethal gene from their mother.
Because the allele is lethal, that means XlY males will not be born.
That means 2/3 of the children will be females, and 1/3 will be males.
They are prokyartic cells
A good passing current is a small wave for example.
-DNA is double stranded,RNA is one stranded
-DNA contains the following nitrogenous bases:Adeninde Guanine Timine Citozine while RNA contains Adeninde Guanine Citozine and Uracil
-DNA function is to contain the information for manufacturing proteins while there are many types of RNA with whole different jobs for example:messanger RNA(mRNA) it coppies a sequence from the DNA strand and takes it to the ribosome in order to be translated as the order for placing aminoacids in the polypeptide strand;transport RNA(tRNA) it is a short RNA strand containing up to 100 nucleotides it takes aminoacids to the ribosome so the polypeptides strand can start to be manufatured from aminoacids in an order inscripted in the mRNA.
