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Index of Subjects --Apple-Mail-91--211711675 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hi Gerald, On 17-Jun-07, at 1:12 PM, Gerald Ruderman wrote: > Chris, > > How do the unisexual species evolve? Not terribly well, which is the long-term problem with this reproductive strategy ... ;-> > Is there some exchange of genetic material between the females or > with the closely related species? No, there's no exchange of genetic material in these tetraploid females. They are able to produce young partheogenetically. Since there is no genetic recombination this really limits the possibility of any evolution. These species are really genetic dead ends that continue to exist for as long as conditions favour them, but if something proves to be an environmental challenge, they have very opportunity to adapt. Cheers! Chris > > c.majka@ns.sympatico.ca wrote: > . . . . > >> I'll note, parenthetically, that this genus of beetles is a very >> interesting one which has been the subject of considerable recent >> genetic research. Most of the species in the genus are normal, >> diploid, >> bisexual species, however, there are four species in the group >> which are >> tetraploid, unisexual (female only) species that reproduce >> parthenogenetically. Unisexuality in beetles is a comparatively rare >> phenomenon. Recent research has established that these tetraploid >> species have resulted from hybridization between two species and >> using nuclear and mitochondrial DNA the maternal and paternal >> "parents" >> of these species have been established. They are: > . . . . >> Most of these species (/philadelphica, alnicola, confluens, rowena, >> multipunctata, & scalaris/) are found in the Maritimes, so this >> region >> is a very interesting laboratory of the development and evolution of >> this species-rich genus (37 species are found in North America, and >> there are many more in neotropical areas). _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _. Christopher Majka - Nova Scotia Museum of Natural History 1747 Summer Street, Halifax, Nova Scotia, Canada B3H 3A6 (902) 424-6435 Email <c.majka@ns.sympatico.ca> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _. --Apple-Mail-91--211711675 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 <HTML><BODY style=3D"word-wrap: break-word; -khtml-nbsp-mode: space; = -khtml-line-break: after-white-space; ">Hi Gerald,<DIV><BR><DIV><DIV>On = 17-Jun-07, at 1:12 PM, Gerald Ruderman wrote:</DIV><BR = class=3D"Apple-interchange-newline"><BLOCKQUOTE type=3D"cite"><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">Chris,</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: = 14px; "><BR></DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">How do the unisexual species = evolve? <BR></DIV></BLOCKQUOTE><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Not=A0terribly well, which = is the long-term problem with this reproductive strategy ... = ;-></DIV><BR><BLOCKQUOTE type=3D"cite"><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Is there some = exchange of genetic=A0material between the females or with the closely = related species?</DIV></BLOCKQUOTE><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>No, there's no exchange of = genetic material in these tetraploid females. They are able to produce = young partheogenetically. Since there is no genetic recombination this = really limits the possibility of any evolution. These species are really = genetic dead ends that continue to exist for as long as conditions = favour them, but if something proves to be an environmental challenge, = they have very opportunity to adapt.</DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Cheers!</DIV><DIV><BR = class=3D"khtml-block-placeholder"></DIV><DIV>Chris</DIV><BR><BLOCKQUOTE = type=3D"cite"><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><A = href=3D"mailto:c.majka@ns.sympatico.ca">c.majka@ns.sympatico.ca</A> = wrote:</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">. . . .</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; min-height: 14px; "><BR></DIV> <BLOCKQUOTE = type=3D"cite"><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">I'll note, parenthetically, that = this genus of beetles is a very</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">interesting = one which has been the subject of considerable recent</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">genetic research. Most of the species in the genus = are normal, diploid,</DIV><DIV style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; ">bisexual species, however, = there are four species in the group which are</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">tetraploid, unisexual (female only) species that = reproduce</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">parthenogenetically. = Unisexuality in beetles is a comparatively rare</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">phenomenon. Recent research has established that = these tetraploid</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">species have resulted from = hybridization between two species and</DIV><DIV style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">using = nuclear and mitochondrial DNA the maternal and paternal = "parents"</DIV><DIV style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; ">of these species have been = established. They are:</DIV> </BLOCKQUOTE><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">. . . .</DIV> = <BLOCKQUOTE type=3D"cite"><DIV style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; ">Most of these species = (/philadelphica, alnicola, confluens, rowena,</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">multipunctata, & scalaris/) are found in the = Maritimes, so this region</DIV><DIV style=3D"margin-top: 0px; = margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">is a very = interesting laboratory of the development and evolution of</DIV><DIV = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">this species-rich genus (37 species are found in = North America, and</DIV><DIV style=3D"margin-top: 0px; margin-right: = 0px; margin-bottom: 0px; margin-left: 0px; ">there are many more in = neotropical areas).</DIV> </BLOCKQUOTE></BLOCKQUOTE></DIV><BR><DIV> <P = style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><FONT face=3D"Times" size=3D"3" = style=3D"font: 12.0px = Times">_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._= ._._._.</FONT></P> <P style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><FONT = face=3D"Times" size=3D"3" style=3D"font: 12.0px Times">Christopher Majka = - Nova Scotia Museum of Natural History</FONT></P> <P style=3D"margin: = 0.0px 0.0px 0.0px 0.0px"><FONT face=3D"Times" size=3D"3" style=3D"font: = 12.0px Times">1747 Summer Street, Halifax, Nova Scotia, Canada<SPAN = class=3D"Apple-converted-space">=A0 </SPAN>B3H 3A6</FONT></P> <P = style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><FONT face=3D"Times" size=3D"3" = style=3D"font: 12.0px Times">(902) 424-6435 <SPAN = class=3D"Apple-converted-space">=A0 </SPAN>Email <<A = href=3D"mailto:c.majka@ns.sympatico.ca">c.majka@ns.sympatico.ca</A>></F= ONT></P> <P style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><FONT face=3D"Times"= size=3D"3" style=3D"font: 12.0px = Times">_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._= ._._._.</FONT></P> </DIV><BR></DIV></BODY></HTML>= --Apple-Mail-91--211711675--
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