Parenage testing, coat colors, and Mutt Tests Flashcards
what percent of mammalian genome consists of sequence repeates
50% ; simple sequence repeats here are most important (n tandem direct repetitions of 1-4bp); microsatalies 1-13 repeat units long; allelic like a gene more variable than a gene; depending on repeats might have diff #s of repeated; more of these than genes
parentage testing
look at markers and see what offspring has if its something old one of possible parents has that is most likely the parent but you can’t confirm parentage can just rule it out this way
- exclusion of parent is 100% accurate, conformation of a parent is not
- multiple sires is permitted by AKC
non-informative marker
could be from multiple sires/ dams in question so doesn’t indicate who parent is or where this came from; need markers with diff genes to rule parenting in/ out; the more markers you have the more informative
Melanoblasts
- derived from trunk neural crest cells
- distributed throughout body underneath keratinocytes and present in iris (this is why melanoma can be so bad)
- adrenal medula and DRG are derivatives from same area
- clinically important in disease state like melanoma
melanin synthesis
melanosome -> keratinocyte -> skin/ hard darkening
C locus- makes color (albino lacks big c); this makes you have tyrosine
E locus- direct which way color goes (black brown yellow); ee= recessive = yellow to red color
B locus- black and brown variation BB/ Bb= black; bb= Brown; this determines nose and eye lid/ lash color in yellow labs
ee
yellow color depends on the the breed (Irish setter vs white poodle)
Coat color loci
- A: Agouti locus in dogs recessive (striped hair shaft); in cats dominant -> tabby color
- B: B- black b- brown’
- C: C- full color c- albino, Cs- siamese (temperature dependent dark spots on coldest spots)
- D: D- full color d- dilution (distribution) (black-> grey, brown -> fawn)
- E: increase eu/pheomel ratio; e= only pheomel
- K: Kb= solid black; KBr: solid and agouti = brindle; Ky= only agouti color
- M: M- merele, m- normal
- S: Spotting; in dogs s spots, in cats S spots
Agouti
eumalinin and pheomelanin banded hair (GSD, abysinian cat, tabby cats)
Yellow lab mom chocolate dad with black male pups, brown female pups and yellow female and male pups
- mom is Bb, ee (ee bc yellow Bb bc has Black/ brown pups and has black nose)
- dad is bb Ee bb bc brown Ee bc has yellow pups but also black and brown pups
Calico cats
O: X linked O=orange O+ = non orange OO orange female OY orange male OO+ calico female O+O+= non orange, base color female O+Y= non orange, base color male Orange= orange or yellow Base color= black or brown
Only 1 x is expressed per cell but random which cell expressed which X which is why heterozygous female ends up with calico color
male calico cat
XXY (can also be xx/xy but usually XXY)
Black hair follicular dysplasia
white hair normal
Black areas hairless bc hair breaks off (clumped melanin, large macromelanosomes, hair shafts small, distorted, and twisted; melanophages in peribulbar dermis)
color diultion alopecia
similar to black hair follicular dysplasia; best described in blue dobermans (diluted black dobermans); mange-like coat; not all dilutes will have problem; 80% dilute dobermans will have chronic atopic dermatitis; D>dcda>d
dilute dogs have a lot of alopecia dermatitis; often mange like coat
Merle
M locus; incomplete dominate (dominant trait but may not always be seen)
avoid MM because comes with issues (retrotransposon insertion) -> ocular and auditory abnormalities, deafness, increased ocular pressure, micropthalmia, colobomas
Rhodesian ridgebacks dilute coat
dilute coat and blue iris 4/7 affected; had decrease in cerebellum size and decrease in purkinje cell numbers; other affected dog was way back 4 geneatons
Dalmatians with hyperuricosuria (stone formation)
- dalamtions homozygous for huu
- all non white Dalmatians homozygous for MITF
- spots coded by T dominant and spot modifier linked to huu
- stone formation is linked to color (spot size linked to dx so the selecting for color accidentally also selected for stone formation)
Coat color and dx examples
- lethal white spotting in foals (defect in endothelial B receptor)
- Mutations in Ckit
- Ws in mice, stem cell aplasia
- megacolon in rats and other species
- Waardenburg in humans (white hair patch linked with other health issues)
- white spotting in dogs is associated with deafness in ear that has spot on it/ near it
- Hereford cattle- white ears not associated with deafness
why do mutt tests
- curiosity
- dog is old and owner ones one like it again
- potential for genetic dx
- legal (dangerous dog laws, apartment rentals)
mutt of mutts
1st generation 50/50 of each parent all look similar to each other
2nd generaiton- mix all these up and get many potential offspring that look v different (if size variant in parents of first generation have size difference then 1st generation will all be around same size and 2nd generation will have 1/4 small 1/2 midsize 1/4 large)
mutt dna test accuracy
some are pretty accurate some are less accurate; depends on library they have to go off of
optimal selection
dogs and cats; screen for 150 and 30 genetic dx respoecity and 15 and 20 traits respectively; breeder tool to ensure greater diversity
mutt tests
- accuracy depends on breeds in databaes
- not a guarantee for same dog
- most tests do not identify pitbulls ( don’t want to be involved in breed specific legislation)
- May help ID potential for genetic dx or traits
parentage confomration
- exclusion of parent 100% accurate, conformation is not; multiple sires permitted by AKC
Coat colors are importnat
- clinical features of dx
- paternity issues
- prevention of dx
- disease discovery
