Inheritance of sex linked genes... Flashcards
(24 cards)
Question: What type of chromosome determines what sex an organism develops as?
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Answer: The type of chromosome that has the genes that determine what sex the organism develops as are the sex chromosomes
Question: What are genes found on a sex chromosome known as?
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Answer: Genes found on a sex chromosome are known as sex-linked genes
Question: What are genes on the X-chromosome called?
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Answer: On the X-chromosome, genes are called “X-linked”
Question: What are genes on the Y-chromosome called?
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Answer: On the Y-chromosome, genes are called “Y-linked” or “holandric”
Question: In mammals, what combination of sex chromosomes results in a female?
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Answer: In mammals, inheriting XX results in a female.
Question: In mammals, what combination of sex chromosomes results in a male?
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Answer: In mammals, inheriting XY results in a male.
Question: In birds and reptiles, what combination of sex chromosomes results in a male?
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Answer: In birds and reptiles, inheriting ZZ results in a male.
Question: In birds and reptiles, what combination of sex chromosomes results in a female?
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Answer: In birds and reptiles, inheriting ZW results in a female.
Question: Which Y-linked gene in mammals results in a male phenotype?
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Answer: The Y-linked gene “SRY” (sex-determining region of the Y-chromosome) results in a male phenotype in mammals
Question: What type of protein is the SRY gene?
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Answer: The SRY gene is a transcription factor
Question: Approximately when is the SRY gene expressed during embryological development?
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Answer: The SRY gene is expressed around the 7-week point of embryological development.
Question: How does the SRY gene lead to male sexual characteristics?
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Answer: It enhances the transcription of some genes and represses the transcription of others, leading to male sexual characteristics
Question: Do the X and Y chromosomes have the same genes?
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Answer: No, the X and Y chromosomes are not homologous, therefore they don’t have the same genes
Question: Does the X-chromosome have an allele of the SRY gene?
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Answer: No, the X-chromosome has no allele of the SRY gene.
Question: Which are more common: Mendelian or non-Mendelian patterns of inheritance?
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Answer: Non-Mendelian patterns of inheritance are more common
Question: Name four common non-Mendelian patterns of inheritance.
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Answer: Four common non-Mendelian patterns of inheritance are Incomplete dominance, Codominance, Polygenic inheritance, and Pleiotropy
Question: What is incomplete dominance?
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Answer: Incomplete dominance is when neither allele is able to completely mask the phenotype encoded by the other
Question: In incomplete dominance, how do heterozygotes display a phenotype?
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Answer: Heterozygotes display a phenotype that is a blend or average of the phenotypes encoded by each allele
Question: What is codominance?
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Answer: Codominance is when the phenotype of both alleles show through simultaneously in heterozygotes
Question: What is polygenic inheritance?
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Answer: Polygenic inheritance is when more than one gene contributes towards the same phenotype
Question: What type of phenotypes (related to inheritance patterns) are most likely to be influenced by the environment?
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Answer: Phenotypes resulting from Polygenic inheritance are the most likely to be influenced by the environment
Question: What is epistasis?
Answer: Epistasis is a specific example of polygenic inheritance when one gene can completely mask the effects of another gene
Question: Is epistasis the same as dominance?
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Answer: No, the source explicitly states, “Careful: this is not the same as dominance!”.
Question: What is pleiotropy?
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Answer: Pleiotropy is when one gene contributes towards many different phenotypes
