Genetics Flashcards
How many pairs of chromosomes in humans?
23
How many pairs are autosomal chromosomes? How many are sex chromosomes?
22
1
Karyotype
visual representation of chromosomes arranged in order of size.
used in diagnosis of chromosomal disorders
Epigenetic changes
heritable changes in gene expression that do not involve changes in genetic code
Epigenetic changes include
DNA methylation
modification of histones
DNA methylation affects… it methylates … and it …. with age.
gene expression
cytosine
decreases
There are … locations in the genome where methylation varied the most. About one third of those regions occurred in genes linked to increase risk of …
18,000
cancer
DNA methylation greater than …% in children at age 5 was tied to a …% increase in body fat 9-10 years later.
10%
12%
DNA mutations can happen
replication or damaged by environmental agents
Point mutations affect…
What types?
one nucleotide
substitution mutations
insertion mutations
deletion mutations
Dominant allele if present is … expressed. Recessive allele is … only if found on both alleles.
always
expressed
How many mutations known for single-gene disorders?
6000
Single-gene disorders are classified by inheritance patterns…
autosomal recessive and dominant
Autosomal recessive and dominant effect …. children equally.
male and female
X-linked single gene disorders are mostly…
recessive