Inheritance Patterns Flashcards

single gene

1
Q

what are genetic complexities beyound dominant and recessive?

A

Alleles have a dominance hierarchy that has to be determined if more than one allele is present (if 2 or more alleles are on the local)

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2
Q

What is MC1R ?

A

melanoreceptor gene - Ed is donimamnt black or ee which is a true red (only omozygous res will show red

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3
Q

where is the pigment diposited

A

the the root of hair or skin

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4
Q

what are the two different types of MC1R pigments

A

Phaeomelanin - producing red, yellow and cream
Eumelanin - producing black, brown and grey

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5
Q

when does black occur

A

in every heterozygous dominant pattern and recessive pattern
red only shows up in homozygous recessive

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6
Q

what is MC1R E+

A

wild type - the colour is influenced by other genes

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7
Q

What is the dominance hierarchy of alleles

A

ED>E+>e

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8
Q

what colours do they make

A

EDED- black
E+E+ - brown/wild type
ee - red
EDE+ black
EDe - black
E+e - brownish

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9
Q

what is codominant?

A

both phenotypes expressed together but observed seperately

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10
Q

what is incomplete dominance

A

both phenotypes are expressed as a blended appearnce

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11
Q

what are some autosomal recessive generalizations

A
  • most are enzyme deficiencies (inborn errors of metabolism)
  • phenotype is generally consistent
    symptoms are severe (present at birth and often lethal)
    consanguinity common (from ancestors)
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12
Q

what does autosomal recessive mean

A

recessive because neither parent actually looks infected

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13
Q

what are the exceptions for consistent phenotypes

A

von willebrand disease
cone-rod dystrophy

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14
Q

what are examples of carrier detection tests?

A

breedin tests(NEED TO KNOW DISEASE), direct tests(biochemical, DNA tets for the mutation) and indirect linkage tests for DNA

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15
Q

what is the breeding test

A

mate a sire of interest to either affected dams or heterozygous carrier dams and see if any affected offspring is born
if yes the sire is a carrier

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16
Q

what is the spider syndrome

A

severe skeletal abnormality
don’t survive very long
used to do the breeding test but now do the DNA testing

17
Q

what is a direct biochemical test?

A

deficiency of betamannosidase in a homozygous recessive cause an affect gene dosage

18
Q

what is direct DNA testing

A

most tests are PCR - whihc amplifies small amounts of DNA (HAIR ROOTS, BUCCAL SWAB, BLOOD, SEMEN)

19
Q

what is indirect DNA linkage testing

A

used when causation gene isnt known yet
location of gene, or biochemical pathway is know
less accurate then direct tests - depends on distance of marker to gene

20
Q

What is a marker?

A

its linked to the causative gene
DNA variation within an intron or other noncoding segment
markers do not affect any phenotype so have accumulated in animals

21
Q

what is polycystic kidney disease

A

autosomal dominant
persian cats and breeds with persians
cysts developes by 12 months
renal failure later in life
premature stop codon in PKD1 gene

22
Q

what is sex-linked?

A

gene on the sex chromosome
due to unequal sizes of chromosomes heterogametic sex has fewer genes

23
Q

What is sex linked traits

A

effects the sexes differently

24
Q

What are X-linked diseases

A

muscular dystrophy in dogs
factor VII hemophilia in horses and dogs
females have to be heterozygous to be effected, males just need X chromosome to be effected to be infected - males are effected young ans are unlikely to bred

25
what happend in hemophilia or horses?
males show their genotype, females to not
26
what are examples of X lnked traits
down silver gold colour in chicken sexing and fast slow primary feather growth in chickens
27
what is Y linked?
Holandric - transmitted only through males gene for primary sex characteristics (sry) penis and scrotum genetic condition of dense hair in ears in men from india
28
what is sex influenced
more sex hormones can influence it - comb and wattle size in poultry mahogany color of Ayrshire cattle scurs
29
what are scurs
wiggle horns (not attached to the skull) begin growing at 4 months in age gene on chromosome 19 - not identified yet bulls need only one copy to grow scurs - females need two copies all scurred cattle P/p not P/P all female scures are Sc/Sc - cull
30
what is epistasis?
genotype at one locus able to mask the phenotype cause by the genotype at another locus ex. albinism masks colour of hair eyes hoof - all of which are controlled by different genes