Unit 3 - Genetics

Question 1

What is the definition of Laws of Inheritance?

Answer 1

Parental lines; F1 generation; F2 generation; Crosses

Question 2

how towrite a 血统 Pedigrees?

Answer 2

Males (squares), Female (circle), need to look at manula p41

Question 3

What are Alleles? 等位基因

Answer 3

Allele refers to the various forms a particular gene can take.
-all animals have two alleles. These may be the same, or different.

Question 4

Genotype versus Phenotype

Answer 4

-The outward appearance of a person, animal or plant is called its phenotype.
-The true genetic makeup (the nature of its alleles) is called its genotype.

Question 5

Is dominant alleles always desirable?

Answer 5

No, Dominant alleles are not always desirable; recessive alleles are not always defective

Question 6

Homozygous versus Heterozygous纯合子和杂合子

Answer 6

The terms homozygous and heterozygous describe whether an individual animal or person has two alleles that are the same, or two alleles that are different for a given characteristic.

 An individual with the genotype CC or cc is homozygous for the characteristic o Their two alleles are identical
 An individual with the genotype Cc is heterozygous for the characteristic

Question 7

Carriers

Answer 7

Heterozygous individuals are sometimes called carriers, because they carry a recessive gene that can be passed on to their offspring but individually do not show the characteristic.

Question 8

Test crosses

Answer 8

The test cross is performed to determine the genotype of a dominant parent if it is a heterozygous or homozygous dominant. On the basis of the results obtained in the ratio of the offspring, it can be predicted that the parent is having which genotype.

Question 9

What is the difference between heterozygous and homozygous dogs?

Answer 9

Dogs that are more heterozygous have received a higher number of diverse genes from their father and mother. In contrast, dogs that are more homozygous inherited more of the same genes from their father and mother.

Purebred - Also called HOMOZYGOUS and consists of gene pairs with genes that are the SAME. Hybrid - Also called HETEROZYGOUS and consists of gene pairs that are DIFFERENT.

Question 10

Hybrids

Answer 10

offspring of a cross between two purebred animals
-purebred dogs are often subject to many diseases

Question 11

Independent Assortment

Answer 11

 Dog 1 has a genetic defect for blindness and a black coat colour
 Dog 2 has normal vision and a white coat colour
 Offspring will inherit their parent’s genes for coat colour and the genes for vision; however, the two are inherited separately

Question 12

Use of Punnett Squares for Multiple Genes

Answer 12

庞尼特方格是遗传学中一种有用的工具，用于预测基因型和表现型的可能组合
The Punnett square is useful in determining the possible outcomes of a cross involving more than one characteristic (A and B on separate genes).

Question 13

Expression of the X and Y Chromosomes

Answer 13

only a few genes on the Y chromosome but there are many genes on the X chromosome.

Question 14

Lethal and Detrimental Genes

Answer 14

致命和有害基因

Question 15

Selective Breeding

Answer 15

the animal’s owner (farmer or breeder) wishes to achieve the best quality offspring from each mating, and selects the animal’s mate on that basis

Question 16

What are artificial selection and natural selection?

Answer 16

The selection of an animal’s mate based on the genotype of each animal is called artificial selection. This differs from natural selection in which an animal chooses its own mate, presumably at random.

Question 17

how to get improvment quickly in breeding?

Answer 17

Mating based on a single characteristic will produce the desired results more quickly

Question 18

What are the traits have high heritability?

Answer 18

Collie eye syndrome (high heritability) and hip dysplasia ( medium heritability)

Question 19

Mutation

Answer 19

a change in DNA structure which may be present in a single cell or in every cell of the body.

Question 20

Genetic Diseases

Answer 20

Disease results when the incorrect protein cannot perform essential bodily functions.
e.g Eye defects in Collies; Deafness in Dalmatians

Question 21

What are the collection method of DNA testing?

Answer 21

-Buccal Swab Sample Collection: The collection of epithelial cells from the lining of the cheek using a swab technique should not be used on dogs under 6 weeks of age.

-Blood Sample Collection: Cause a small amount of bleeding by trimming the dog’s nail short or by pricking the paw pad with a sterile needle.

-dewclaw or Docked Tail Sample Collection: After removal place the dewclaw or tail in a paper envelope (avoid plastic, as the sample could grow bacteria or decay in plastic).

Question 22

Parentage Profiles

Answer 22

血统概要文件 crossmatch of DNA
Each offspring receives two copies, called alleles, one from each parent in a random process.
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