Genetics 2

Front 1

mapping

Back 1

process of locating specific genes to their physical location on chromosomes

Front 2

two approaches to mapping

Back 2

1. genetic mapping - looks at inheritance patterns in families and establishes the order of the genes on the chrom

2. physical mapping - uses various methods of tagging the chrom w/physical markers to establish positions of genes or other DNA sequences on the chromonsomes

Front 3

synteny

Back 3

2 genes of DNA seq reside on the same chrom
greek = "same strand"

Front 4

linkage

Back 4

2 genes or DNA sequences are inherited together more than expected by random chance

-probability concept

-genes MUST be syntenic if they are linked

- genes are not nec linked just bc they are syntenic b/c of crossing over

Loci on the same chromosome that experience recombination less than 50% of the time are said to be linked

Front 5

centimorgan

Back 5

distance between loci
1 cM represents a recombination frequency of approximately 1%
theta - stands for centimorgans

Front 6

assessing linkage in families

Back 6

statistical odds that 2 loci are a given number of cM apart can be calculated by measuring the ratio of:
- the likelihood of linkage at some specified linkage distance
-the likelihood of no linkage (theta =50cM)

- Ratios that are >1.0 reflect odds in favor of linkage
- Ratios < 1.0 reflect odds against linkage

The statistical odds that two loci are a given number of centimorgans apart can be calculated by measuring the ratio of two likelihoods: the likelihood of linkage at a given recombination frequency divided by the likelihood of no linkage
-

Front 7

LOD score

Back 7

The logarithm of this odds ratio is a LOD score. LOD scores of 3.0 or higher are taken as evidence of linkage, and LOD scores lower than -2.0 are taken as evidence that the two loci are not linked

Front 8

linked marker criteria

Back 8

to be useful
- codominant
- numerous
- highly polymorphic - increases the probability that matings will be informative

Front 9

personal biochemistry

Back 9

we have a unique biochem environment in which the biochem ( both macro and smlr molecules are in a dynamic process of change

Front 10

phenylketonuria

Back 10

deficiency of phenylalanine hydrozylase
causes a build up of phenylalanine
(blocks it from being converted to tyrosine)

Front 11

tyrosine - negative oculocutaneous albinism

Back 11

deficiency of tyrosinase

causes a build up of dopamine (blocks it from becoming melanin)

Front 12

alkaptonuria (AKU)

Back 12

deficiency of homogentisic acid oxidase

build up of Homogentisic acid (blocks it from being converted into maleylacetoacetate )

excreted in large quantities in urine -darken on standing
"black urine dx"
HGA depositied in CT resulting in abn pigmentation and debilitating artheritis

loss of fn mutation

Front 13

tyrosinemias

Back 13

deficiency of fumarylacetoacetate hydrolase

build up of fumarylacetoacetate ( not broken down into fumarate and acetoacetate)

Front 14

how are most metabolic disorder inherited?

Back 14

autosomal recessive
heterozygous carriers usually doesn't affect health

Front 15

How are metabolic disorders tested for?

Back 15

dried blood and analyzing for elevated levels of metabolintes in newborn period

carrier and diagnostic testing becoming widely more available