exam Flashcards
What are the determining features on a pedigree chart that would indicate autosomal recessive?
Typically not seen in every generation. Passed on by two asymptimatic carriers. Males and females equally likely to inherit
what are the determining features on a pedigree chart that would indicate autosomal dominant
Typically present in every generation. Affected individuals have an affected parent. Males and females equally likely to inherit
What are the determining features on a pedigree chart that would indicate x linked recessive
Fathers cannot pass X linked traits to their sons. Sons get it from their mothers. Most often affects males
Why was the human genome sequenced (5 reasons) ?
find out what genes made up the human genome and what their role is
How many genes make up the genome
Analyse genetic info between humans
sequence the genome of several model organsims
and to provide fast information to people
What were the key findings from sequencing the human genome?
20,000 different genes
20% of the genes we dont know their purpose
the genome is dynamic
less than 2% of the genome codes for proteins
All humans are 99.9% simular at the sequence level
what are the 4 ways that genomes among individuals vary
SNP’s ( single nucleotide polymorphisms)
STR’s ( short tandem repeats)
InDels (short insertions or deletions)
CNV’s( copy number varients)
what does comparitive genetics tell us about genomes?
used to discover what is common and what is different. compare sequences by aligning and looking at the differences
How are disease causing genes found within next generation sequencing
what does a dominant mutation cause
what does a recessive mutation cause
causes a phenotype when heterozygous
causes a phenotype only when homozygous
what is a loss of function mutation
breaks a gene so it doesnt work as well or not at all.
(often recessive as a normal copy of the chromosome exists which can replace the loss of function one)
what is a gain of function mutation?
a mutation causing a gene to work too well or do something unexpected.
(gain of function are often dominant, having a allele that works too well will not be replaced by the normal copy of the gene)
how are disease causing genes found in with next generation sequencing?
1) sequence the genome
2) compare to the human reference
3) look at the parts that differ.
4) if they are predicted to be harmful validate and test them.
what are polygenetic disorders and eg.
several genes acting together or envrionmental factors acting on genes
eg obesity, diabetes, bipolar
what are monogenetic diseases and eg.
inhertiance of a single gene mutation
eg haemophilia A& B
what is gene determinism
disease comes through a range of variants multiple genes and the envrionment.
most genetic disorders are probabilistic not deterministic
your genes do not direct your destiny
