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Genetics
304.4 Vet nursing genetics
Question | Answer |
---|---|
What is a fertilised ovum called? | Zygote |
Genetics is the study of what? | Inheritance |
The basic unit of hereditary expression? | Gene |
How many characteristics does a single gene influence? | One |
What are polygenic characteristics? | A characteristic influenced by multiple genes |
What do you call a long string of genes? | Chromosome |
The position of a gene on a chromosome | Locus |
Identifying the locus of each gene on every chromosome on the cell | Gene mapping |
A gene on the same locus on a pair of homologous chromosomes | Allele |
A pair of identical alleles | Homozygous genes |
A pair of non-identical alleles | Heterozygous genes |
A gene which overrides its allele | Dominant gene |
A gene which is only expressed when in a homozygous pair | Recessive gene |
Alleles giving different instructions for a gene which are both expressed (eg blood type) | Co-dominant gene |
Genes which suppress the activity of other genes (eg albinism) | Epistasis |
The external appearance of an animal | Phenotype |
The genetic makeup of an animal | Genotype |
4 things that may affect the animals phenotype? | Diet, environment, disease, lifestyle |
Number of pairs of chromosomes in the dog | 39 |
Number of pairs of chromosomes in the cat | 19 |
Number of pairs of chromosomes in the human | 23 |
Number of pairs of chromosomes in the horse | 32 |
Name for the chromosomes which are not sex cells | Autosomes |
The only pair of chromosomes which may not be homologous | Sex chromosomes |
Mendel's first law of inheritance | The law of segregation |
Mendel's second law of inheritance | The law of independent assortment |
What is the law of segregation? | During meiosis each gamete only gets one allele from each gene |
What is the law of independent assortment? | Genes for different genes are not linked during meiosis |
Mendel's third law of inheritance | The law of dominance |
What is the law of dominance? | Recessive alleles will always be masked by dominant alleles |
What is a sex linked gene? | Genes located on the sex chromosomes |
Which sex is more likely to show a sex linked genetic problem? | Males |
What is a sex limited gene? | Genes which are switched on or off by reproductive hormones |
What are lethal genes? | Genes incompatible with life |
What is a classically lethal gene? | The animal dies in the womb or shortly after birth |
What is a delayed lethal gene? | Die from a progressive condition later in life |
Semi-lethal gene | Mild abnormalities which may not necessarily kill the animal |
What is a congenital defect? | Defect present in the animal at birth |
Name of the zygote from 0-35 days of age | Embryo |
The fusion of gametes to form a new organism | Fertilisation |