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Genetics Review Study, study, study!! Test tomorrow…

Genetics Review Study, study, study!! Test tomorrow…

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Page 1: Genetics Review Study, study, study!! Test tomorrow…

Genetics Review

Study, study, study!!Test tomorrow…

Page 2: Genetics Review Study, study, study!! Test tomorrow…

List Mendel’s three proposed principles that are recognized as the basis of inheritance.

• The Principle of Dominance• The Principle of

Segregation• The Principle of

Independent Assortment

Page 3: Genetics Review Study, study, study!! Test tomorrow…

Define: Homozygous

•Having identical alleles or pairs of genes•Ex: BB, bb, DD, dd

Page 4: Genetics Review Study, study, study!! Test tomorrow…

Define: Heterozygous

•One gene in the pair is dominant, and the other gene is recessive. •Ex: Bb, Dd

Page 5: Genetics Review Study, study, study!! Test tomorrow…

Define: Zygote

•A fertilized ovum or egg

Page 6: Genetics Review Study, study, study!! Test tomorrow…

Define: Dominant

•Refers to genes that are expressed whether an allele is identical or similar.•Ex: D, B

Page 7: Genetics Review Study, study, study!! Test tomorrow…

Define: Recessive

•Refers to genes that are only expressed when they are paired with an identical allele• Ex: b, d

Page 8: Genetics Review Study, study, study!! Test tomorrow…

In swine, the gene for drooping ears (D) is dominant, while the gene for erect ears (d) is recessive. If two swine are mated, one is heterozygous with

drooping ears and the other is homozygous with erect ears (Dd x dd), what would be the expected offspring outcome?

d d

D Dd Dd

d dd dd

Homozygous drooped ears= 0Heterozygous drooped ears= 2

Homozygous erect ears=2

Page 9: Genetics Review Study, study, study!! Test tomorrow…

When two or more genes influence a trait, an allele of one may have an

overriding effect on the phenotype, such as for comb shapes in chickens.

This is known as:

•Epistasis

Page 10: Genetics Review Study, study, study!! Test tomorrow…

An exception to the principle of dominance occurs when a

heterozygote exhibits traits found in both associated homozygotes, such

as a roan coat color in horses. This is known as:

•Codominance

Page 11: Genetics Review Study, study, study!! Test tomorrow…

When a pure, brown-eyed sheep is crossed with a pure, green-eyed sheep, blue-eyed off-spring are

produced. This is known as:

•Partial dominance

Page 12: Genetics Review Study, study, study!! Test tomorrow…

Sex-linked genes are carried on what?

•The X or Y chromosome

Page 13: Genetics Review Study, study, study!! Test tomorrow…

Genetic improvement can take up to how long to see an

improvement in a trait?

• It can take several generations.

Page 14: Genetics Review Study, study, study!! Test tomorrow…

Is phenotype predetermined?

•NO!! Phenotype is not predetermined by the parents.

Page 15: Genetics Review Study, study, study!! Test tomorrow…

Can genotypic characteristics be measured or observed?

•NO! Only phenotype can be measured or observed.