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Which statement describing DNA is incorrect.

Colorblindness and adrenoleukodystrophy (ALD) are both X linked recessive phenotypes (C = normal; c = colorblind and A = normal; a = adrenoleukodystrophy). The genes are 12 m.u. apart on the X chromosome.  Adult onset cerebral ALD begins in middle age and has a rapid onset to death. Cara’s dad is color blind and has just started showing signs of ALD. Assume there are no recessive alleles on Cara’s mother’s side of the family (i.e., assume Cara is C___A c___a). Cara’s 3-yr old son Oliver has normal vision. What is the probability that Oliver will develop ALD?    

James is mildly affected with the mitochondrial disorder MERRF (myoclonic epilepsy and ragged red fiber disease), due to a mutation in his mtDNA. His partner is phenotypically normal and does not have a family history of mitochondrial disease. What is the likelihood the couple will have a child affected with MERFF?

The rhesus (Rh) blood group gene (Rh positive = R; Rh negative = r) and a gene that causes a form of anemia called elliptocytosis (E = anemia; e = no anemia) show linkage. Of 200 offspring from a cross where one parent is Rh negative with no anemia (r___e r___e) and the other parent is Rh positive with anemia (R___E r___e): 80 are R___E r___e       80 are r­___e r­­­­___e        20 are R___e  r___e       20 are r___E r___e.   Based off these 200 offspring, how many map units apart are the genes? 

If a DNA sample contains 8% guanine, how much adenine does it contain?

A gene is maternally imprinted. Kate receives an affected (mutated) allele from her father and the normal allele from her mother. What is the probability that Kate will have the affected phenotype? 

Shown below are four chromosomes. The blue circles represent genes. The map units (m.u.) describe the distance of separation between genes. Which genes have the lowest recombination frequency?   

A gene is maternally imprinted. Kate receives an affected (mutated) allele from her father and the normal allele from her mother.  Assuming her partner has normal alleles, what will be the expected phenotype of Kate’s offspring? 

Please show both sides of your scratch paper to the camera if you have not already done so. In the cross AaBb x aabb, 4 different offspring categories are produced at equal frequency (i.e., each off the 4 offspring categories are present at a frequency of 25%). Does the outcome suggest independent assortment or genetic linkage of the two genes?

The gene for nail patellar syndrome (n = normal allele; N  = mutant allele) shows linkage to the blood group A, B and O alleles (IA = blood type A; IB = blood type B; i = blood type O). The IA and IB alleles both show complete dominance over the i allele. The IA and IB alleles are co-dominant to each other. The two genes are located 20 m.u. apart. An individual has the following genotype: n____i   N____IA What is the probability that the individual will pass along the chromosome N___IA to offspring?