Patients with Hurler™s syndrome are known to have mutations at the L-iduronidase locus. The diagnosis of Hurler™s syndrome is most efficiently
made by analyzing a patient™s DNA for
a. A region of DNA that does not encode RNA
b. Alternative forms of the L-iduronidase gene
c. The entire set of genes in one leukocyte
d. A nucleotide substitution in the L-iduronidase gene
e. The position of the L-iduronidase gene on a chromosome
The answer is BBBBB.. The most efficient DNA diagnosis would involve analysis
of the two L-iduronidase genes in an individual, looking for any change
in DNA sequence (nucleotide substitutions, deletions, duplications) that
would alter function of the L-iduronidase protein. Alternative forms of a
gene are called alleles, and an allele that has changed during transmission
from parent to child may be called a mutant allele. Many human characteristics
are encoded by genes, each occupying a particular address or locus
on a chromosome. Genes consist of DNA segments that encode RNA along
with flanking DNA sequences that regulate gene expression (see the figures
below). Within the coding regions are DNA segments that are transcribed
and then translated into protein (exons), and those that are transcribed but
removed by RNA splicing (introns). If a DNA mutation produces a disease
through its altered protein, as with L-iduronidase gene mutations in
Hurler™s syndrome, the mutant gene (strictly, the mutant allele) may be
called abnormal. Human autosomes (chromosomes 1 through 22) and X
chromosomes in females have two homologous loci in each individual,
harboring two identical (homozygous) or different (heterozygous) alleles.
Males have only one X chromosome and often only one allele per sex chromosome
locus because the Y has minimal coding material. The complete
set of genetic material (all the genes and loci) in each biological species is
called the genome.
Sorry cant post the figure from explanation but its picture of nucleotide and base forumal..
2bdoctor, what exactly is the mutation of the L-iduronidase gene in hurlers? The explanation given is very ambiguous...
its an AR condition
so need to see for both alllele r mutated r not.
thanks for ans. where did u get the question?!