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| {{Short description|Pattern of inheritance in evolutionary biology}} | |||
| {{Expand section|date=March 2009}} | |||
| ⚫ | ], the Father of Genetics]] | ||
| ]]] | |||
| ]]] | |||
| ⚫ | '''Particulate inheritance''' is a pattern of inheritance discovered by ] theorists, such as ], ] or ] himself, showing that ]s can be passed from generation to generation through "discrete particles" known as ], which can keep their ability to be expressed while not always appearing in a descending generation.<ref>, WebRef</ref> | ||
| ⚫ | ], the Father of Genetics]] | ||
| ⚫ | '''Particulate inheritance''' is a pattern of inheritance discovered by ] theorists |
||
| == Scientific developments leading up to the theory == | == Scientific developments leading up to the theory == | ||
| Early in the 19th century, scientists had already recognized that Earth has been inhabited by living creatures for a very long time. On the other hand, they did not understand what mechanisms actually drove ]. |
Early in the 19th century, scientists had already recognized that Earth has been inhabited by living creatures for a very long time. On the other hand, they did not understand what mechanisms actually drove ]. They also did not understand how ] are inherited from one generation to the next. ] was the common ideal at the time, but was later discredited by the experiments of Gregor Mendel. Mendel proposed the theory of particulate inheritance by using ] plants (''Pisum sativum'') to explain how variation can be inherited and maintained over time.{{cn|date=March 2023}} | ||
| === Blending |
=== Blending model versus particulate model === | ||
| * '''Blending |
* ''']:''' | ||
| ** Offspring are a blend of both parents (i.e. in modern terms, alleles would blend together to form a completely new allele) | ** Offspring are a blend of both parents (i.e. in modern terms, alleles would blend together to form a completely new allele) | ||
| ** The characteristics of the blended offspring are passed on to the next generation | ** The characteristics of the blended offspring are passed on to the next generation | ||
| ** Variation is washed out over time<ref name=bioed>{{cite web |author=Lisa M. Meffert |title=Blending Model of Inheritance vs. Particulate Model of Inheritance |work=Introduction to Mendelian Genetics |url=http://www.bioedonline.org/slides/content-slides/heredity/introduction-to-mendelian-genetics/?pageaction=displaySlideDetails&tk=30&dpg=2 |publisher=BioEd Online |access-date=March 12, 2014 |archive-url=https://web.archive.org/web/20160624175506/http://bioedonline.org/slides/content-slides/heredity/introduction-to-mendelian-genetics/?pageaction=displayslidedetails&tk=30&dpg=2 |archive-date=June 24, 2016 |url-status=dead }}</ref> | |||
| ** Variation is washed out over time<ref>, ''BioEd Online''</ref> | |||
| ⚫ | * '''Particulate model:''' | ||
| ⚫ | ** Offspring are a combination of both parents | ||
| ⚫ | * '''Particulate |
||
| ⚫ | ** Offspring are a |
||
| ** The characteristics of both parents are passed on to the next generation as separate entities | ** The characteristics of both parents are passed on to the next generation as separate entities | ||
| ** Variation is maintained over time<ref |
** Variation is maintained over time<ref name=bioed/> | ||
| == Mendel's |
== Mendel's methods == | ||
| === Mendel's Laws === | |||
| ⚫ | Since Mendel used experimental methods to devise his particulate inheritance theory, he developed three basic laws of inheritance: the ], the ], and the ]:<ref |
||
| === Mendel's laws === | |||
| ⚫ | Since Mendel used experimental methods to devise his particulate inheritance theory, he developed three basic laws of inheritance: the ], the ], and the ]:<ref name=bioed/> | ||
| ⚫ | Mendel's experiment with tall and short pea plants demonstrates how each individual plant has two particles called ]. |
||
| ==== Law of |
==== Law of segregation ==== | ||
| ⚫ | Mendel's experiment with tall and short pea plants demonstrates how each individual plant has two particles called ]. When a pea plant produces ] (reproductive cells), it segregates one allele to each one.{{cn|date=March 2023}} | ||
| ⚫ | The law states that when the parents differ from each other in two or more pairs of contrasting characters, the inheritance of one pair of characters is independent to that of the other pair of characters. |
||
| ==== Law of |
==== Law of independent assortment ==== | ||
| ⚫ | The law states that when the parents differ from each other in two or more pairs of contrasting characters, the inheritance of one pair of characters is independent to that of the other pair of characters.{{cn|date=March 2023}} | ||
| ⚫ | In the pea plants, Mendel observed that the "T" allele (]) masked the effects of the "t" allele (]). The terms "dominant" and "recessive" are used for the masking and the covered allele, respectively. All offspring from this cross are ] in terms of their ]. They also are tall (because the allele for tall masks the allele for short) in terms of their "]".<ref> |
||
| == |
==== Law of dominance ==== | ||
| ⚫ | In the pea plants, Mendel observed that the "T" allele (]) masked the effects of the "t" allele (]). The terms "dominant" and "recessive" are used for the masking and the covered allele, respectively. All offspring from this cross are ] in terms of their ]. They also are tall (because the allele for tall masks the allele for short) in terms of their "]".<ref>{{cite web |author=Lisa M. Meffert |title=Crossing the Parental Lines: Female Contribution |work=Introduction to Mendelian Genetics |url=http://www.bioedonline.org/slides/content-slides/heredity/introduction-to-mendelian-genetics/?pageaction=displaySlideDetails&tk=30&dpg=6 |publisher=BioEd Online |access-date=March 12, 2014 |archive-url=https://web.archive.org/web/20160623133338/http://bioedonline.org/slides/content-slides/heredity/introduction-to-mendelian-genetics/?tk=30&dpg=6&pageaction=displayslidedetails |archive-date=June 23, 2016 |url-status=dead }}</ref> | ||
| * ] | |||
| * ] | |||
| == Fisher == | |||
| * ] | |||
| {{further|Modern synthesis (20th century)}} | |||
| In a 1918 publication titled "The Supposition of Mendelian Inheritance Among Close Relatives," ] showed that particulate inheritance was capable of generating the vast amount of variation we see among closely related individuals. This helped to reconcile the Biometric and Mendelian schools of thought at the time, and was an important step in the ].<ref>{{cite book |last=Larson |first=Edward J. |authorlink=Edward J. Larson |year=2004 |title=Evolution: The Remarkable History of a Scientific Theory |series=Modern Library Chronicles |volume=17 |location=New York |publisher=] |isbn=0-679-64288-9 |lccn=2003064888 |oclc=53483597 |pages= |url-access=registration |url=https://archive.org/details/evolutionremarka00lars/page/221 }}</ref> | |||
| == Notes == | == Notes == | ||
| Line 42: | Line 43: | ||
| == References == | == References == | ||
| * Campbell, N. E. & Reece, J. B. (2002). ''Biology'' (6th ed.). San Francisco: Benjamin Cummings. | * Campbell, N. E. & Reece, J. B. (2002). ''Biology'' (6th ed.). San Francisco: Benjamin Cummings. | ||
| * "Particulate inheritance." ''BioEd Online''. Retrieved 3-5-2009 from | * "Particulate inheritance." ''BioEd Online''. Retrieved 3-5-2009 from | ||
| Line 48: | Line 48: | ||
| {{DEFAULTSORT:Particulate Inheritance}} | {{DEFAULTSORT:Particulate Inheritance}} | ||
| ] | ] | ||
| ] | ] | ||
Latest revision as of 00:48, 18 August 2024
Pattern of inheritance in evolutionary biology
Particulate inheritance is a pattern of inheritance discovered by Mendelian genetics theorists, such as William Bateson, Ronald Fisher or Gregor Mendel himself, showing that phenotypic traits can be passed from generation to generation through "discrete particles" known as genes, which can keep their ability to be expressed while not always appearing in a descending generation.
Scientific developments leading up to the theory
Early in the 19th century, scientists had already recognized that Earth has been inhabited by living creatures for a very long time. On the other hand, they did not understand what mechanisms actually drove biological diversity. They also did not understand how physical traits are inherited from one generation to the next. Blending inheritance was the common ideal at the time, but was later discredited by the experiments of Gregor Mendel. Mendel proposed the theory of particulate inheritance by using pea plants (Pisum sativum) to explain how variation can be inherited and maintained over time.
Blending model versus particulate model
- Blending model:
- Offspring are a blend of both parents (i.e. in modern terms, alleles would blend together to form a completely new allele)
- The characteristics of the blended offspring are passed on to the next generation
- Variation is washed out over time
- Particulate model:
- Offspring are a combination of both parents
- The characteristics of both parents are passed on to the next generation as separate entities
- Variation is maintained over time
Mendel's methods
Mendel's laws
Since Mendel used experimental methods to devise his particulate inheritance theory, he developed three basic laws of inheritance: the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance:
Law of segregation
Mendel's experiment with tall and short pea plants demonstrates how each individual plant has two particles called alleles. When a pea plant produces gametes (reproductive cells), it segregates one allele to each one.
Law of independent assortment
The law states that when the parents differ from each other in two or more pairs of contrasting characters, the inheritance of one pair of characters is independent to that of the other pair of characters.
Law of dominance
In the pea plants, Mendel observed that the "T" allele (dominant) masked the effects of the "t" allele (recessive). The terms "dominant" and "recessive" are used for the masking and the covered allele, respectively. All offspring from this cross are heterozygotes in terms of their genotypes. They also are tall (because the allele for tall masks the allele for short) in terms of their "phenotype".
Fisher
Further information: Modern synthesis (20th century)In a 1918 publication titled "The Supposition of Mendelian Inheritance Among Close Relatives," R.A. Fisher showed that particulate inheritance was capable of generating the vast amount of variation we see among closely related individuals. This helped to reconcile the Biometric and Mendelian schools of thought at the time, and was an important step in the modern synthesis.
Notes
- "Particulate theory of inheritance", WebRef
- ^ Lisa M. Meffert. "Blending Model of Inheritance vs. Particulate Model of Inheritance". Introduction to Mendelian Genetics. BioEd Online. Archived from the original on June 24, 2016. Retrieved March 12, 2014.
- Lisa M. Meffert. "Crossing the Parental Lines: Female Contribution". Introduction to Mendelian Genetics. BioEd Online. Archived from the original on June 23, 2016. Retrieved March 12, 2014.
- Larson, Edward J. (2004). Evolution: The Remarkable History of a Scientific Theory. Modern Library Chronicles. Vol. 17. New York: Modern Library. pp. 221–243. ISBN 0-679-64288-9. LCCN 2003064888. OCLC 53483597.
References
- Campbell, N. E. & Reece, J. B. (2002). Biology (6th ed.). San Francisco: Benjamin Cummings.
- "Particulate inheritance." BioEd Online. Retrieved 3-5-2009 from BioEd Online Slides
