I am working on eye colour mutants of house cricket (white - W and yellow - Y, wild type, black - B). I conducted series of genetical crosses to check how observed traits (genes) are inherited. I observed phenotypes gradation: black (WW/YY) > yellow (WW/yy) > white (ww/yy). When I cross B x Y in F2 I get typical 3:1 (B:Y), cross of Y x W in F2 give 3:1 (Y:W) too. So nothing special, typical singel gene results. But in cross of B x W I observed that phenotype distribution doesnt fit to theoretical. In my basic model in F2 there sholud be phenotypes proportion 9:6:1 (B:Y:W) but results show: 10:1,8:1,2 (parent generation: black female x white male) or 9,8:2,6:0,6 (parent generation : black male x white female). For some reason genotypes ww/Yy and ww/YY (expected yellow eyes) probably are lethal, that is why there is less yellow eye individuals. I dont know what genes are mutated, they are signed just for model usage (but probably some genes from ommochromes/tryptophan metabolic pathway, check https://www.researchgate.net/publication/304784316_Porownanie_skladu_barwnikow_wzrokowych_w_oczach_linii_mutantow_bialo-_i_zoltookich_swierszcza_domowego_Acheta_domesticus/Compare of eye pigments content in eye-coloured mutants of Acheta domesticus).
Maybe do you have any idea what is going on, why genotypes WW/yy, ww/yy are ok but ww/YY is not.
Poster Porównanie składu barwników wzrokowych w oczach linii mutant...
Hi, you could check the distributions from your F2 by chi-squared test. The chi-squared test could be used to determine whether there is a significant difference between the expected frequencies of phenotype (9:6:1 in your hypothesis) and they observed frequencies. I suppose in case of your results it could not be any significant differences, but you could check it.
Hi, thank you for the answer. I think I have found the solution of my problem. It looks like the lost part of crickets is simply black eyed. In this model phenotype distribution is 12:3:1 (B:Y:W). In this case observed distribution fits much better to model. But still,I have checked the distributions by chi2 test and it is not ok, observed distribution is eqaul 12,3 : 2,2 : 1,4 or 12 : 3,2 : 0,78. Chi2 test shows that it is statistically different from model 12:3:1 (one experiment was made in 12 repetition, 4000 insects counted) . Something strange happend with yellow/white proportion when black (WWYY) is crossed with white (wwyy).
Yes, it is most probably explenation. We have made hatching test of offspring from interstrain (WxB, YxW, YxB) crosses. In case of WxB hatchability is much lower. This observation can explain strange proportion of phenotypes.
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