HLTB22H3 Lecture Notes - Lecture 7: R.W.D. Molenbeek, Zygosity, Allele

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pearseal162

25 Jan 2017

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UTSC

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Health Studies

Course

HLTB22H3

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Document Summary

Bioa11- lecture 7 mendelian genetics and complex patterns of inheritance review. Module 2: cell la vie (lecture 7 based on: chapter 8) Extensions of mendelian genetics: patterns of inheritance that are a little more complex than simple ones in which genes are inherited in a straightforward manner (controlled by a single gene with a dominant and a recessive allele) Rr = red flowers rr = white flowers. Codominance: the heterozygote"s phenotype is a combination of two fully expressed traits (combination) R1r2 = roan coat color (red and white) Two different alleles of a gene are both expressed in an individual. Polygenic traits: traits that are affected by the interactions among many genes. Blood typing: technique that scientists use to help determine relatedness of people. Involves determining if certain carbohydrates are located on the surface of red blood cells. These surface markers are part of the abo blood system. Displays 2 extensions of mendelism: codominance and multiple allelism.

Related Questions

These all relate to exceptions to the inheritance patterns encountered by Mendel.â

Why do multiple and lethal alleles often result in modifications of the classic Mendelian monohybrid and dihybrid ratios?

Select the four correct statements.

-When an essential gene is mutated, it can result in a lethal phenotype. There are no classic Mendelian monohybrid and dihybrid ratios.

-In the case of codominance, heterozygotes produce gene products from both alleles of a gene. Classic Mendelian monohybrid and dihybrid ratios are modified by codominance.

-In the case of incomplete dominance, the phenotype of the heterozygote is distinct from and often intermediate to the phenotypes of homozygous individuals. Classic Mendelian monohybrid and dihybrid ratios are modified by incomplete dominance.

-Genes exist in a large number of allelic versions and a diploid organism has two homologous gene loci that may be occupied by different alleles of the same gene. This can result in many different phenotypes for traits, which may not follow typical Mendelian ratios.

-When an essential gene is mutated, it can result in a lethal phenotype. This results in a modification of classic Mendelian ratios.

-The phenotype of the heterozygous genotype is distinct from and often intermediate to the phenotypes of the homozygous genotypes. The joint expression of both alleles in a heterozygote is called codominance. There are no classic Mendelian monohybrid and dihybrid ratios.

-Genes exist in a large number of allelic versions, but in a diploid organism, only one allele of the gene can occupy one homologous gene loci. Classic Mendelian inheritance cannot explain this phenomenon.

-Each gene produces a unique gene product. The effect of one allele in a heterozygote completely masks the effect of the other. Classic Mendelian genetics cannot explain this phenomenon.

A woman with normal vision is pregnant from a man with red-green colorblindness. Can they child produce a child that has red-green colorblindness?

		Yes. It is possible for them to produce a child with red-green colorblindness.
		No. It is impossible for them to have a child with red-green colorblindness

Assuming gene linkage a cross female fruit fly with yellow body and white eyes with a male fruit fly with a grey body and red eyes would produce male offspring with which phenotype combination?

		yellow body and white eyes
		yellow body and red eyes
		grey body and white eyes
		grey body and red eyes

Blended inheritance is supported by which genetic discovery?

		incomplete dominance
		gene linkage
		codominance
		independent assortment

Crossing over during meiosis violates the prediction of _____.

		gene linkage
		segregation
		XY sex determinism
		codominance

Phenotypes that have a range of variability (not discrete differences such as Mendel's pea flower color), are typically a result of ______.

		polygenic inheritance
		independent assortment
		gene linkage
		segregation

HLTB22H3 Lecture Notes - Lecture 7: R.W.D. Molenbeek, Zygosity, Allele

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