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Hello. The topic of this lecture is genetic 
diseases in rabbits and chinchillas. The lecture

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is part of Module 4, Precision Livestock Farming. 
The creation of this presentation was supported

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by the ERASMUS+ KA2 grant within the project 
ISAGREED, Innovation of Content and Structure of

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Study Programs in the Field of Animal Genetic and 
Food Resources Management Using Digitalization.

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What are genetic diseases? A genetic 
disease occurs when mutations affect

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the function of genes, resulting in 
physical or functional deviations

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from the normal state with a negative 
impact on vitality. There are many types

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of genetic diseases, including monogenic, 
multifactorial, and chromosomal disorders.

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Causes of genetic diseases include 
mutations and their transmission to

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the next generation of offspring. Genetic 
diseases are divided into three groups:

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Monogenic diseases -> mutations in one gene 
(on one or both chromosomes) - for example,

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cystic fibrosis, sickle cell anemia 
(mainly metabolic disorders).

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Multifactorial inherited diseases -> a combination 
of variability in many genes and the environment

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(quantitative, complex diseases) - heart 
diseases, diabetes, most types of cancer,

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hip dysplasia in dogs. Chromosomal diseases 
-> increase or decrease in the number

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and functions of genes through changes in the 
number or structural changes of chromosomes.

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Genetic nature of domestic rabbits The domestic 
rabbit (Oryctolagus cuniculus) is one of the

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most recently domesticated species (probably 
in the last 1,500 years) and is characterized

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by exceptionally high phenotypic diversity - 
there are more than 200 breeds known worldwide.

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Breeds differ significantly in weight, 
body structure, fur type, fur color,

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and ear length, and this visible morphological

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variability exceeds the phenotypic 
diversity of their wild counterparts.

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Normal rabbits serve as a model for studying 
human diseases such as hyperlipidemia and related

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diseases, cancer and diabetes mellitus, 
tuberculosis, papillomavirus infection,

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atherosclerosis, obesity and type II diabetes, 
prion diseases, lung and airway morphometry.

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Rabbits are used as bioreactors for the production 
of pharmaceutical proteins - for example,

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recombinant human C1 inhibitor in milk.
Transgenic/gene-edited rabbits

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are widely used as model organisms for biomedical 
research. In the last decade, more than fifty

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rabbit models with gene knockouts or knock-ins 
have been described. Rabbits have a new role

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as specialized tools, especially as models for 
imaging organs and tissues in situ and in vivo.

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The genome of a rabbit according to the OryCun2.0 
assembly has a size of 2.7 Gbp and contains 20,613

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protein coding genes. The rabbit genome was 
fully sequenced for the first time in 2009.

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There is a database of Mendelian traits in animals 
- OMIA.org. Currently, there are a total of 125

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traits recorded in rabbits, out of which 75 have 
a proven Mendelian trait or disease, and 16 have

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a determined gene and causal mutation.
Some of the autosomal

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recessive diseases in rabbits include:
Oculocutaneous albinism type I (OCA1),

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TYR-related: The TYR gene (tyrosinase) located 
on chromosome 1. The 1118C>A substitution leads

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to a missense mutation (Thr>Lys) at codon 373.
Abnormal gait, retinal dysplasia, cataracts:

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Disrupts saltatorial locomotion. The proven gene 
is RORB (RAR-related orphan receptor B) located on

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chromosome 1, with a mutation in the same allele - 
g.61103503G>A (in the 5' donor site of intron 9).

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Adrenal hyperplasia: Results in death immediately 
after birth due to hypersecretion of adrenaline.

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The responsible gene is CYP11A1 (cytochrome P450, 
family 11, subfamily A, polypeptide 1), with an

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ah allele - a large deletion mutation.

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Long hair: Regulates hair growth. The 
gene is FGF5 (fibroblast growth factor

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5) located on chromosome 15. There is a 
missense mutation, c.571T>C, p.(L191S).

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Autosomal incomplete dominance: Dwarfism

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with the HMGA2 gene (high mobility group AT-hook 
2) on chromosome 4. The dw allele is a deletion,

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covering approximately 12.1 kb overlapping the 
promoter region and the first three exons of

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the HMGA2 gene, resulting in gene inactivation.
Chinchilla (Chinchilla lanigera): Chinchillas

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are rodents belonging to the family Chinchillidae 
and are closely related to guinea pigs and degus.

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There are two species of chinchillas, Chinchilla 
chinchilla (short-tailed chinchilla) and

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Chinchilla lanigera (long-tailed chinchilla). The 
chinchilla genome has a total sequence length of

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2.39 Gbp, with a diploid chromosome number of 64.

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It contains 17809 protein–coding genes.
Fur chewing: Many captive chinchillas

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exhibit fur chewing behavior. This behavior 
not only affects the fur price but can also

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have negative physiological and productive 
consequences, impacting animal welfare.

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The estimated heritability is h2 = 0.16. To reduce 
the occurrence of this behavior, improvement

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in selection and management practices used in 
fur-bearing animal breeding should be implemented.

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Urinary stones (Urolithiasis) occur in 
chinchillas: The formation of stones

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in the urinary tract or a condition associated 
with the presence of these stones. There is no

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direct evidence that this disorder is inherited in 
chinchillas. However, it was included because the

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same disorder is undoubtedly hereditary in other 
species, and there is no reason to believe that

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the same situation does not apply to chinchillas.
Skin diseases in chinchillas include:

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Fur slip: Loss of fur often occurs 
when handling chinchillas roughly or

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when they are extremely stressed. The 
lost fur regrows but may take some time.

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Fur ring: Fur rings commonly occur in male 
chinchillas. A ring of fur can wrap around

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the penis inside the prepuce. This 
ring needs to be removed before it

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constricts blood flow to the tip of 
the penis. Males, especially those

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in breeding colonies or housed with other 
chinchillas, should be regularly checked.

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Ringworm: Ringworm caused by Trichophyton 
mentagrophytes can cause alopecia in chinchillas.

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The most commonly affected areas are the 
upper part of the nose and ear flaps.

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Treatment for this condition often 
involves adding an antifungal powder

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to a sand bath. These conditions are also 
considered to have a hereditary predisposition.

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Infertility is another serious condition in 
chinchillas. Poor reproduction can be caused by

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several possible factors, including malnutrition, 
abnormal sperm, hormonal imbalance, infectious

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diseases, lack of experience, and lethal genes 
from inappropriate crossbreeding. For example,

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mating between chinchillas with the same genes 
for white and velvet fur color should be avoided.

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Infectious and dietary factors and 
poor overall health can also cause

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infertility in both male and female chinchillas.

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And thank you for your attention.