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 Pedigree and Southern Blot Question  

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  • 100/5
  • 1
  • 2
  • 3
  • 4
  • 5

Author18 Posts

See picture...


A. 100
B. 50
C. 33
D. 25
E. 0


PLEASE EXPLAIN!! smiling face


wher is the pic


.here is the pic... sorry it didn't attach first time.

Attached Files:
Genetics.JPG (42 KB, 186 downloads)

A. 100%


no. not A





if is ressesive 25%


If is autosomic DOMINANT is 50%
if is autosimic Ressesive is 25 %


E is right... can you explain Robin?


yes please


It does not matter to me

thanks for the post



look III3 and III4

Both are males and receive X chromosome from their mother.

Both are phenotypically normal so their X chromosome is normal--> upper X chromosomes is normal.

II4 is father, has one X normal.

III 2 recieves one normal X from father and the normal other from mother. she carries both normal X--> 0%

at first I only looked at father and though lower X is noraml and the upper one is abnormal. I should be careful for such question


tricky one


Thanks... I figured it out by the pedigree only... You don't need the info withthe bands to solve it, right?


U figure out that the alleles in the 2 normal sons are differentand hence BOTH are normal. if the bands werent there , we'd have to calculate risk of being a carrier etc


yes i see it now... II-5 has two normal X's so her kids are normal.


hello, I am finding it tough to understand the qs especially the box with dashes and roman numerals,forgive me for sounding like a lay man ,I think step1 will force me to come face to face with all the nightmares i avoided back in medical school......gulp!!, so please can any one spoon feed me.....thanx!rolling eyes


.....well I guess I figured it out after some cool thinking,sorry 4 the trouble guys ,I get scared early,and 4 those who r as repulsive of genetics as i m let me decipher the facts to help others,here goes..(only 4 mediocres!!)

ii4,ii5------------are just the labels (x,y axis)for dad and mom of the woman concerned(shown with an arrow)

the bars in the box are genetic mapping of the x chromosomes of men and women ,hence only one bar for a male and two for femal to show the distribution of different x chromosomes of the mother since there is a chance that the same x chromosome might have been reused in both iii3 and iii4 as studying pointed out.
THE PEDIGREE is an XR as no females are diseased.
in an XR carrier mother atleastr50% of her son has to be affected which is not a case here so ii-5 is innocent,not a carrier,ie has no defective X to give to her daughter which may accept one of her x chromosome ,the other X comes from her father who is normal so cant have defective X (no carriers possible in males,eithr dsd or normal)

so the iii-2 female is proved not to be a carrier . QIDgrin

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