It is known that the white eye B gene of Drosophila is controlled by autosomal recessive gene. If there is only one white eye in every 2500 Drosophila in the population, what is the frequency of white eye B gene?

It is known that the white eye B gene of Drosophila is controlled by autosomal recessive gene. If there is only one white eye in every 2500 Drosophila in the population, what is the frequency of white eye B gene?

According to hardy Weinberg law, the frequency of gene B is 1 / 50 = 2%

How many gametes can male Drosophila with two alleles produce? Two or four?

The gene of male Drosophila is completely linked (distinguishing female Drosophila), so it can only produce two kinds of gametes. Assuming its genotype is AABB, it can produce AB, AB or AB, ab

As shown in the figure, the quadrilateral efgh is a cross section of the spatial quadrilateral ABCD. If the cross section is a parallelogram, prove: BD ‖ plane efgh

The ∵ section efgh is a parallelogram, ∵ eh ∩ plane BCD, ∵ eh ⊊ plane BCD, FG ⊂ plane BCD, ∩ plane BCD = BD.. Eh ∩ BD.. Eh ⊂ plane efgh, BD ⊊ plane efgh, ∩ BD ∩ plane efgh

If AB is perpendicular to CD, ab = a, CD = B, and E is the midpoint of AD, the area of efgh is calculated

Let CG / BC = k, then BG / BC = 1-k, so Hg / CD = BG / BC = 1-k, so Hg = CD (1-k) = B (1-k), so GF = AB * k = AK, so efgh Because it is a parallelogram, EF is parallel to GH, so EF is parallel to the plane where GH is located, BCD, and because EF belongs to ACD, EF is parallel to the intersection line of ACD and BCD, CD, so GH is parallel to CD. Similarly, GF is parallel to AB, AB is perpendicular to CD, so GH is perpendicular to GF, so efgh is rectangular, so the area is Hg * GF = Abk (1-k) & lt; = AB * 0.5 * 0.5 = 1 / 4AB