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Title: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: KendraJo on Apr 30, 2014 You decide to designate the alleles of the four loci as either additive (contributing to fruit segment number and represented by a superscript “+”) or non-additive (not contributing to fruit segment number and represented by a superscript “0”). Using this convention, choose the correct genotype for the two pure lines and the F1, and indicate how many additive alleles each genotype has.
Complete the diagram below by dragging one blue label to each blue target and one pink label to each pink target. Labels may be used once, more than once, or not at all. Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: padre on Apr 30, 2014 HI Kendra
See if this helps :down: Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: brooklyn09 on Apr 30, 2014 a) First let's go through the matings, assuming pr and vg are on different chromosomes. In the following notation, alleles above the horizontal line are from one homologous chromosome, and alleles below the line are from the other homologous chromosome.
Parents: pr vg x pr+ vg+ pr vg pr+ vg+ F1: pr vg pr+ vg+ F1 backcross: pr vg male x pr vg female pr+ vg+ pr vg Expect in F2: male gametes: pr vg pr vg+ pr+ vg pr+ vg+ _____________________________ ____________ female gametes pr vg | pr pr vgvg pr pr vg+vg pr+pr vgvg pr+pr vg+vg This predicts four different phenotypes, purple vestigial, purple long-winged, red-eyed vestigial, and red-eyed long-winged, in equal numbers (each comprising 0.25 of the progeny). b) The actual results were markedly different. In fact none of the recombinant phenotypes, purple long-winged and red-eyed vestigial, were observed. This indicates that the purple and vestigial genes are linked. Subsequent mapping showed that they are both in the second linkage group (Drosophila has four linkage groups, corresponding to three autosomes and one pair of sex chromosomes). Note that no measurable recombination occurred between the purple and vestigial genes in this backcross; this is a peculiarity of male Drosophila and the heterogametic sex in some other species. Other experiments with heterozygous F1 females do show recombination (see part 1c). Let's re-examine the predictions of the matings, now that it is clear that the genes are linked. In the notation below, a horizontal line with more than one gene above and below it means that the genes are linked. Again, alleles for one homologous chromosome are above the line, and those for the other chromosome are below it. Parents: pr vg x pr+ vg+ pr vg pr+ vg+ F1: pr vg pr+ vg+ F1 backcross: pr vg male x pr vg female pr+ vg+ pr vg Expect in F2: male gametes: pr vg pr+ vg+ _____________________ female gametes pr vg | pr vg pr+ vg+ pr vg pr vg Thus in the absence of recombination, one obtains equal numbers of purple vestigial and red-eyed long-winged flies in the progeny. c) In this case, the mating is F1 backcross: pr vg female x pr vg male pr+ vg+ pr vg and recombination does occur (as mentioned in 1.1b, the absence of recombination is peculiar to male Drosophila). Note that the frequency of recombinant types is much less than the 50% predicted for no linkage (see 1.1a). The purple long-winged flies have the genotype pr vg+ pr vg and red-eyed vestigial flies have the genotype pr + vg pr vg in both cases resulting from recombination between the purple and vestigial genes. The combined number of recombinants comprises 15.2% of the progeny, and one concludes that the two genes are linked, and are 15.2 map units, or 15.2 centiMorgans apart. Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: padre on Apr 30, 2014 Awesome :)
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: KendraJo on Apr 30, 2014 Yes thank you for the help!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: padre on May 1, 2014 NP
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: doxikal on Jul 28, 2014 Thank you Padre!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: mekelley on Dec 7, 2014 Thank you! This really helped!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: Kelly Thompson on Mar 27, 2020 .
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: ntjamerson on Mar 29, 2020 Thank you so much!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: HMBD33 on Apr 26, 2020 Thank you!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: Edison Bai on Apr 27, 2020 This makes sense now Thank You
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: anth1894 on Apr 27, 2020 Thank you!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: Victoria Blackwell on Jul 13, 2020 Thank you!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: bee12345 on Sep 7, 2020 Thank you
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: seyi on Oct 6, 2020 thank you
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: Flight on Oct 25, 2020 Thank you!
Title: Re: Determining parental and F1 genotypes in crosses involving polygenic inheritance Post by: Leanna Rabinovitch on Nov 16, 2020 Thank you!
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