Given the following sequence of genes on a chromosome, what change in chromosome structure occurred (the * indicates the centromere)? before A B C D * E F G H    after    A B C D * E F E F G H   

An individual has the sex chromosome genotype XXX. How many Barr bodies does the individual possess in each of their somatic cells? 

A mother is mildly affected with a mitochondrial disease. As she is only mildly affected, she decides to have 3 children. Her first child is also mildly affected. However, her second child is moderately affected, and her third child was severely affected and died in infancy. How can the three children display such different phenotypic variation?

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 on a recombinant chromosome to offspring (any recombinant chromosome)? 

What is the complement DNA strand to 5′ – GGA CGT – 3′?   

Fill in the blanks below: Heterochromatin is _________ than euchromatin and heterochromatin has a _________ density of transcriptionally active DNA compared to euchromatin.

Do individuals with monosomy X or trisomy X have any phenotypic symptoms?

During meiosis I there is a non-disjunction of chromosome 11. What would be the genetic make-up of the resulting embryo following fertilization by a normal gamete?

The pedigree below shows the inheritance of a mitochondrial disorder. What is the most likely mode of inheritance for this mitochondrial disorder? Assume complete penetrance.   

Which statement describing DNA is incorrect.