Sex chromosome: Difference between revisions
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<span style="line-height: 19px">A pair of sex [[Chromosomes|chromosomes]] in a diploid organism is the only pair in which the chromosomes are not morphologically similar homologs.</span>There are two [[Chromosome|chromosomes]] responsible for determinig sex of an organism. In most organisms these are the [[X chromosome|X]] and [[Y chromosome|Y chromosomes]].<span style="line-height: 19px"> In humans and most other animals, females are the</span><span style="line-height: 1.5em"> </span>[[Homogametic|homogametic]]<span style="line-height: 1.5em"> sex as they inherit two X chromosomes (XX), and males are the </span>[[Heterogametic|heterogametic]] sex<span style="line-height: 1.5em"> as they inherit one X chromosome and one Y chromosome (XY). However in some organisms such as birds, moths, butterflies, some reptiles and some fish, the opposite applies, meaning that </span><span style="line-height: 19px">the male is the homogametic sex (XX) and the female is the heterogametic sex (XY).<ref>Hartl, D. L., Ruvolo, M. (2011) pp131-136 Genetics: Analysis of Genes and Genomes, 8th ed., Burlington: Jones &amp;amp;amp; Bartlett Learning, LLC</ref></span> | <span style="line-height: 19px">A pair of sex [[Chromosomes|chromosomes]] in a diploid organism is the only pair in which the chromosomes are not morphologically similar homologs.</span>There are two [[Chromosome|chromosomes]] responsible for determinig sex of an organism. In most organisms these are the [[X chromosome|X]] and [[Y chromosome|Y chromosomes]].<span style="line-height: 19px"> In humans and most other animals, females are the</span><span style="line-height: 1.5em"> </span>[[Homogametic|homogametic]]<span style="line-height: 1.5em"> sex as they inherit two X chromosomes (XX), and males are the </span>[[Heterogametic|heterogametic]] sex<span style="line-height: 1.5em"> as they inherit one X chromosome and one Y chromosome (XY). However in some organisms such as birds, moths, butterflies, some reptiles and some fish, the opposite applies, meaning that </span><span style="line-height: 19px">the male is the homogametic sex (XX) and the female is the heterogametic sex (XY).<ref>Hartl, D. L., Ruvolo, M. (2011) pp131-136 Genetics: Analysis of Genes and Genomes, 8th ed., Burlington: Jones &amp;amp;amp;amp; Bartlett Learning, LLC</ref></span> | ||
The inheritance of different sex chromosomes comes about as the homogametic parent always passes on an X chromosome in their gametes and the heterogametic parent will either pass on an X chromosome (producing a homogametic embryo) or a Y chromosome (producing a heterogametic embryo). Roughly half the gametes produced by the heterogametic parent will contain an X chromosome and roughly half will contain a Y chromosome, meaning that the ratio of males to females in the offspring will be roughly 1:1.<ref>Hartl, D. L., Ruvolo, M. (2011) pp131-136 Genetics: Analysis of Genes and Genomes, 8th ed., Burlington: Jones &amp;amp;amp; Bartlett Learning, LLC</ref | The inheritance of different sex chromosomes comes about as the homogametic parent always passes on an X chromosome in their gametes and the heterogametic parent will either pass on an X chromosome (producing a homogametic embryo) or a Y chromosome (producing a heterogametic embryo). Roughly half the gametes produced by the heterogametic parent will contain an X chromosome and roughly half will contain a Y chromosome, meaning that the ratio of males to females in the offspring will be roughly 1:1.<ref>Hartl, D. L., Ruvolo, M. (2011) pp131-136 Genetics: Analysis of Genes and Genomes, 8th ed., Burlington: Jones &amp;amp;amp;amp; Bartlett Learning, LLC</ref> | ||
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Revision as of 16:18, 9 November 2015
A pair of sex chromosomes in a diploid organism is the only pair in which the chromosomes are not morphologically similar homologs.There are two chromosomes responsible for determinig sex of an organism. In most organisms these are the X and Y chromosomes. In humans and most other animals, females are the homogametic sex as they inherit two X chromosomes (XX), and males are the heterogametic sex as they inherit one X chromosome and one Y chromosome (XY). However in some organisms such as birds, moths, butterflies, some reptiles and some fish, the opposite applies, meaning that the male is the homogametic sex (XX) and the female is the heterogametic sex (XY).[1]
The inheritance of different sex chromosomes comes about as the homogametic parent always passes on an X chromosome in their gametes and the heterogametic parent will either pass on an X chromosome (producing a homogametic embryo) or a Y chromosome (producing a heterogametic embryo). Roughly half the gametes produced by the heterogametic parent will contain an X chromosome and roughly half will contain a Y chromosome, meaning that the ratio of males to females in the offspring will be roughly 1:1.[2]
References
- ↑ Hartl, D. L., Ruvolo, M. (2011) pp131-136 Genetics: Analysis of Genes and Genomes, 8th ed., Burlington: Jones &amp;amp;amp; Bartlett Learning, LLC
- ↑ Hartl, D. L., Ruvolo, M. (2011) pp131-136 Genetics: Analysis of Genes and Genomes, 8th ed., Burlington: Jones &amp;amp;amp; Bartlett Learning, LLC